National Landslide HazardsMitigation Strategy—A Framework for Loss ReductionCircular 1244U.S. Department of the InteriorU.S. Geological SurveyLandslide overview map of the conterminous United States. Different colors denote areas of varying landslide occurrence. FromU.S. Geological Survey, 1997, Digital compilation of landslide overview map of the conterminous United States: U.S. GeologicalSurvey Open-File Report 97–0289, digital compilation by Jonathan W. Godt, available on the web athttp://greenwood.cr.usgs.gov/pub/open-file-reports/ofr-97-0289/.Front cover. Massive landslide at La Conchita, California, a small seaside community along Highway 101 north of Santa Barbara.This landslide and debris flow occurred in the spring of 1995. Many people were evacuated because of the slide, and the housesnearest the slide were completely destroyed. Fortunately, no one was killed or injured. Photograph by R.L. Schuster, U.S.Geological Survey.National Landslide HazardsMitigation Strategy—A Framework for Loss ReductionBy Elliott C. Spiker and Paula L. GoriCircular 1244U.S. Department of the InteriorU.S. Geological SurveyU.S. Department of the InteriorGale A. Norton, SecretaryU.S. Geological SurveyCharles G. Groat, DirectorU.S. Geological Survey, Reston, Virginia: 2003Free on application toU.S. Geological SurveyInformation ServicesBox 25286, Federal CenterDenver, CO 80225For more information about the USGS and its products:Telephone: 1–888–ASK–USGSWorld Wide Web: http://www.usgs.govAny use of trade, product, or firm names in this publication is fordescriptive purposes only and does not imply endorsement bythe U.S. Government.Library of Congress Cataloging in Publications DataSpiker, Elliott C.National landslide hazards mitigation strategy : a framework for loss reduction / byElliott C. Spiker and Paula Gori.p. cm.-- (Circular ; 1244)Includes bibliographical references.1. Landslide hazard analysis--United States. I. Gori, Paula. II. Title. III. U.S.Geological Survey circular ; 1244.QE599.U5S65 2003.363.34’9--dc212002044779PrefaceHouse Report 106–222 accompanying the Interior Appropriations Bill for fiscalyear 2000 (as incorporated in Public Law 106–113) states, "The committee isconcerned over the lack of attention given to the Survey’s landslide program.Because of this concern, the Survey is directed to develop by September 15,2000, a comprehensive strategy, including the estimated costs associated withaddressing the widespread landslide hazards facing the Nation. The preparationof this strategy should include the involvement of all parties having responsibility for dealing with the problems associated with landslides."In fulfillment of the requirements of Public Law 106–113, the United States Geological Survey submits this circular, which describes a national strategy toreduce losses from landslides. The circular includes a summary of the Nation’sneeds for research, monitoring, mapping, and assessment of landslide hazardsnationwide.iiiContentsPreface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iiiExecutive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Losses from Landslide Hazards in the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7A National Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11The National Landslide Hazard Mitigation Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Reaching the Goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Major Elements and Strategic Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Element 1. Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Element 2. Hazard Mapping and Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Element 3. Real-Time Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Element 4. Loss Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Element 5. Information Collection, Interpretation, Dissemination, and Archiving . . . . 20Element 6. Guidelines and Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Element 7. Public Awareness and Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Element 8. Implementation of Loss Reduction Measures . . . . . . . . . . . . . . . . . . . . . . . 24Element 9. Emergency Preparedness, Response, and Recovery . . . . . . . . . . . . . . . . . 26Action Items for a National Strategy for Reducing Losses from Landslides . . . . . . . . . . . . . . . . 28Key Steps for Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Management Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28New and Enhanced Roles and Partnerships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Funding for the USGS to Implement a National Strategy for Reducing Lossesfrom Landslides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Expansion of the Work Performed by Scientists in the Landslide Hazards Program . . . 31Establishment of a New Cooperative Landslide Hazard Assessment andMapping Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Establishment of a New Cooperative Federal Land ManagementLandslide Hazards Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Establishment of New Partnerships for Landslide Hazard LossReduction Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Funding Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Major Accomplishments and Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Appendix 1. Previous Reports and Sources of Landslide Hazards Information . . . . . . . . . . . . . 35Appendix 2. Meetings with Stakeholders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Appendix 3. Landslide Hazards and Other Ground Failures—Causes and Types . . . . . . . . . . . . 39Appendix 4. Landslide Hazards Mitigation Strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Appendix 5. Landslide Hazards Maps and Risk Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Appendix 6. Current Landslide Research and Mitigation Activities and Responsibilitiesin the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46Appendix 7. Federal Agency Landslide Hazard Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48vHighlights1. Massive Landslide at Thistle, Utah . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52. Wildfires and Debris Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83. Building Disaster-Resistant Communities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104. Debris-Flow Flume—Understanding Landslide Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . 125. Mapping Debris-Flow Hazards in Madison County, Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . 156. Real-Time Monitoring of Active Landslides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177. Inventory of Slope Failures in Oregon for Three 1996–97 Storm Events . . . . . . . . . . . . . . . . 198. Warning of Potential Landslides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219. Alerting the Public to the Hazards of Mount Rainier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2310. Cincinnati, Ohio—A Leader in Landslide Loss Reduction Measures . . . . . . . . . . . . . . . . . . . 2511. Daly City—The Human Cost of Landslides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Figures1–4. Photographs showing—1. Massive landslide at Thistle, Utah, 1983 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52. Debris flow near Glenwood Springs, Colorado, 1994 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83. Landslide in northwest Seattle, Washington . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104. Debris-flow flume, 45 miles east of Eugene, Oregon, constructed to conductcontrolled experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125. Portion of debris-flow hazard map, Madison County, Virginia . . . . . . . . . . . . . . . . . . . . . . . 156. Diagram showing network for transmission of real-time landslide data . . . . . . . . . . . . . . . 177. Photograph showing scientist measuring landslide movement . . . . . . . . . . . . . . . . . . . . . . 178. Photograph showing scientists testing a solar-powered radio telemetry system forremote transmission of real-time landslide data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179. Landslide-inventory map for three 1996–97 storm events in Oregon . . . . . . . . . . . . . . . . . . 1910. Photographs showing debris flow in Pacifica, California, and house (inset) atedge of debris flow, 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2111. Map showing hazard zones from lahars, lava flows, and pyroclastic flowsfrom Mount Rainier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2312. Photograph showing earthflow in Cincinnati, Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2513. Photograph showing gully retreat threatening evacuated houses inDaly City, California, 1998 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275–1. Maps of part of Seattle, Washington, showing (A) landslide inventory, (B) landslidesusceptibility, (C), Probability of landslide occurrence, (D) Probability of landslidedamage, and (E) Risk of loss due to landslides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44Table1. New roles and partnership opportunities under the National Landslide HazardsMitigation Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29viNational Landslide HazardsMitigation Strategy—A Framework for Loss ReductionBy Elliott C. Spiker and Paula L. Gori"Science by itself will not protect us. Federal, State, and local governments, the private sector, volunteerand charitable organizations and individual citizens must work together in applying the science to makeour communities safer."—Charles Groat, Director of the U.S. Geological SurveyThis circular outlines the key elements of a comprehensive and effectiveExecutivenational strategy for reducing losses from landslides nationwide and providesan assessment of the status, needs, and associated costs of this strategy. The circular is submitted in compliance with a directive of Public Law 106–113 (seepreface). A broad spectrum of expert opinion was sought in developing thisstrategy report, as requested by the U.S. Congress in House Report 106–222.The strategy was developed in response to the rising costs resulting fromlandslide hazards in the United States and includes activities at the National,State, and local levels, in both the public and private sectors. The strategygives the Federal Government a prominent role in efforts to reduce losses dueto landslide hazards, in partnership with State and local governments. TheU.S. Geological Survey (USGS) has taken the lead in developing the strategyon behalf of the large multisector, multiagency stakeholder group involved inlandslide hazards mitigation. The USGS derives its leadership role in landslidehazard-related work from the Disaster Relief Act of 1974 (Stafford Act). Forexample, the Director of the USGS has been delegated the responsibility toissue disaster warnings for an earthquake, volcanic eruption, landslide, orother geologic catastrophe (1974 Disaster Relief Act 42 U.S.C. 5201 et seq).The National Landslide Hazards Mitigation Strategy includes developingnew partnerships among government at all levels, academia, and the privatesector and expanding landslide research, mapping, assessment, real-time monitoring, forecasting, information management and dissemination, mitigationtools, and emergency preparedness and response. Such a strategy uses newtechnological advances, enlists the expertise associated with other related hazards such as floods, earthquakes and volcanic activity, and utilizes incentivesfor the adoption of loss reduction measures nationwide.Summary1The strategy envisions a society that is fully aware of landslide hazardsand routinely takes action to reduce both the risks and costs associated withthose hazards. The long-term mission of a comprehensive landslide hazardmitigation strategy is to provide and encourage the use of scientific information, maps, methodology, and guidance for emergency management, land-useplanning, and development and implementation of public and private policyto reduce losses from landslides and other ground-failure hazards nationwide.The 10-year goal is to substantially reduce the risk of loss of life, injuries,economic costs, and destruction of natural and cultural resources that resultfrom landslides and other ground-failure hazards.This comprehensive National Landslide Hazards Mitigation Strategyemploys a wide range of scientific, planning, and policy tools to address various aspects of the problem to effectively reduce losses from landslides andother ground failures. It has the following nine major elements, spanning acontinuum from research to the formulation and implementation of policyand mitigation:•••••••••Research.—Developing a predictive understanding of landslideprocesses and triggering mechanismHazard mapping and assessments.—Delineating susceptible areas anddifferent types of landslide hazards at a scale useful for planning anddecisionmakingReal-time monitoring.—Monitoring active landslides that pose substantial riskLoss assessment.—Compiling and evaluating information on the economic impacts of landslide hazardsInformation collection, interpretation, and dissemination.—Establishing an effective system for information transferGuidelines and training.—Developing guidelines and training for scientists, engineers, and decisionmakersPublic awareness and education.—Developing information and education for the user communityImplementation of loss reduction measures.—Encouraging mitigationactionEmergency preparedness, response, and recovery.—Building resilientcommunitiesIn each of the above nine elements above, the USGS has a significant role;however, the USGS is not the lead for all elements.2Landslide hazards mitigation requires collaboration among academia, government, and the private sector. Aggressive implementation of a comprehensive and effective national landslide hazards mitigation strategy requiresincreased investment in landslide hazard research, mapping and monitoring,and mitigation activities. Reducing losses from landslide hazards can beaccomplished in part by expanding the existing USGS Landslide HazardProgram, as follows:••••Expansion of research, assessment, monitoring, public information,and response efforts by USGS scientists ($8 million annually)Establishment of a Cooperative Landslide Hazard Assessment andMapping Program to increase the efforts of State and local governments to map and assess landslide hazards within their jurisdictionsthrough competitive grants ($8 million annually, to be augmentedwith 30 percent matching funds by the States and local jurisdictions)Establishment of a Cooperative Federal Land Management LandslideHazard Program to increase the capability of the National ParkService, U.S. Forest Service, Bureau of Land Management, andother such organizations to address landslide hazards under theirjurisdictions ($2 million annually for work performed by USGS scientists on public lands)Establishment of a Partnerships for Landslide Hazard Loss ReductionProgram to support research and implementation efforts by universities, local governments, and the private sector through competitivegrants ($2 million annually)Total new funding required for full implementation of the National LandslideHazards Mitigation Strategy within the USGS is estimated to be approximately $20 million annually.An effective National Landslide Hazards Mitigation Strategy also dependson stronger partnerships among Federal, State, and local governments and theprivate sector in the areas of hazard assessments, monitoring, and emergencyresponse and recovery. The strategy recommended in this circular advocatesenhanced coordination among Federal, State, and local agencies to partnereffectively with the academic and the private sectors and to leverage sharedresources under the leadership of the USGS.3Introduction4Landslides and other forms of ground failure affect communities all acrossthe Nation. Despite advances in science and technology, these events continueto result in human suffering, billions of dollars in property losses, and environmental degradation. As our population increases and our society becomes evermore complex, the economic and societal costs of landslides and other groundfailures will continue to rise.We have the capability as a Nation to understand and identify these hazards and to implement mitigation measures. For many years, the U.S.Geological Survey (USGS), the States, numerous universities, and the privatesector have been grappling with understanding and reducing landslide hazards,and they have developed an extensive body of knowledge (see appendix 1 forsources of information). However, to achieve the goal of significantly reducinglosses from landslide hazards, we need a much more comprehensive scientificunderstanding of landslide processes and occurrence, a robust monitoring program to warn of impending danger from active landslides, a much greater public awareness and understanding of the threat and the options for reducing therisk, and action at the local level.A significant, sustained, long-term effort to reduce losses from landslidesand other ground failures in the United States will require a national commitment among all levels of government and the private sector. The FederalGovernment, in partnership with State and local governments, must provideleadership, coordination, research support, incentives, and resources to encourage communities, businesses, and individuals to undertake mitigation to minimize potential losses and to employ mitigation in the recovery following landslides and other natural hazard events.The USGS is the recognized authority for understanding landslide hazardsin the United States and the long-time leader in this area. The USGS derivesits leadership role in landslide-hazard-related work from the Disaster ReliefAct of 1974 (Stafford Act). The Director of the USGS has been delegated theresponsibility to issue disaster warnings for an earthquake, volcanic eruption,landslide, or other geologic catastrophe consistent with the 1974 DisasterRelief Act 42 U.S.C. 5201 et seq.As requested by the U.S. Congress in House Report 106–222, the USGShas prepared this National Landslide Hazards Mitigation Strategy on behalf ofthe large multisector, multiagency stakeholder group involved in landslideresearch and mitigation nationwide. A number of stakeholder workshops wereheld during 1999 and 2000 with representatives of government and privateorganizations, academicians, and private citizens to seek their opinion andinput (see appendix 2 for more information about the stakeholder workshops).The 1983 Thistle landslide beganmoving in the spring of 1983 inresponse to ground-water buildupfrom heavy rains the previousSeptember and melting snowpackfrom the winter of 1983. Within a fewweeks, the landslide dammed theSpanish Fork River, consequentlyobliterating U.S. Highway 6 and themain line of the Denver and RioGrande Western Railroad (fig. 1).The town of Thistle was inundated by the floodwaters rising behindthe landslide dam. Eventually a drainsystem was engineered to drain thelake and avert a potential disaster.The landslide reached a state of equilibrium across the valley, but fears ofreactivation caused the railway toconstruct a tunnel through bedrockaround the slide zone at a cost of millions of dollars. The highway likewisewas realigned around the landslide.When the lake was drained, residualmuck partially buried the town, and virtually no one returned to Thistle. Totalcosts (direct and indirect) incurred bythis landslide exceeded $400 million,making this the most costly singlelandslide event in U.S. history.Figure 1. The 1983 Thistle landslide,central Utah. Thistle Lake, whichresulted from damming of the SpanishFork River, was later drained as a precautionary measure. This view, takenabout 6 months after the slideoccurred, shows the realignment of theDenver and Rio Grande WesternRailroad lines in the lower center andthe large cut for rerouting U.S.Highway 6/50 on the extreme left sideof the photograph.Photograph by R.L. Schuster, U.S.Geological Survey.Highlight 1—Massive Landslide atThistle, Utah5The National Landslide Hazards Mitigation Strategy provides a framework for reducing losses from landslides and other ground failures.Although the strategy is national in scope, it is not exclusively Federal oreven exclusively governmental. Mitigation, defined as any sustainedaction taken to reduce and eliminate long-term risk to life and property,generally occurs at the State and local levels, and the strategy is based onpartnerships with stakeholders at all levels of government and in theprivate sector.The National Landslide Hazards Mitigation Strategy described hereincorporates many ideas and recommendations of previous studies andreports that expressed the need for a national strategy to address naturalhazards, including landslides and other ground failures (see appendix 1).These earlier studies and reports should be referred to for more in-depthdiscussions of and insights into landslide hazard mitigation and researchneeds. The National Landslide Hazards Mitigation Strategy builds on theprinciples, goals, and objectives of the National Mitigation Strategy—Partnerships for Building Safer Communities, developed in 1996 by theFederal Emergency Management Agency (FEMA) to encourage mitigationof all forms of natural hazards in the United States.The term "landslide" describes many types of downhill earth movements, ranging from rapidly moving catastrophic rock avalanches anddebris flows in mountainous regions to more slowly moving earth slidesand other ground failures. In addition to the different types of landslides,the broader scope of ground failure includes subsidence, permafrost, andshrinking soils. This report focuses on landslides, the most critical groundfailure problem facing most regions of the Nation. However, the NationalLandslide Hazards Mitigation Strategy provides a framework that can beapplied to other ground-failure hazards (see appendix 3 for more information about different types of landslide hazards and other forms of groundfailure).6Landslides are among the most widespread geologic hazards on Earth.Losses from LandslideLandslides cause billions of dollars in damages and thousands of deaths andHazards in the Unitedinjuries each year around the world. Landslides threaten lives and property inStatesevery State in the Nation, resulting in an estimated 25 to 50 deaths and damage exceeding $2 billion annually. Although most landslides in the UnitedStates occur as separate, widely distributed events, thousands of landslides canbe triggered by a single severe storm and earthquake, causing spectaculardamage in a short time over a wide area.The United States has experienced several catastrophic landslide disastersin recent years. In 1985, a massive slide in southern Puerto Rico killed 129people, the greatest loss of life from a single landslide in U.S. history. The1982–83 and 1983–84 El Niño seasons triggered landslide events that affectedthe entire Western United States, including California, Washington, Utah,Nevada, and Idaho. The Thistle, Utah, landslide of 1983 caused $400 millionin losses, the most expensive single landslide in U.S. history, and the 1997–98El Niño rainstorms in the San Francisco Bay area produced thousands of landslides, causing over $150 million in direct public and private costs.Landslides are a significant component of many major natural disastersand are responsible for greater losses than is generally recognized. Landslidedamage is often reported as a result of a triggering event—floods, earthquakes,or volcanic eruptions—even though the losses from landsliding may exceed allother losses from the overall disaster. For example, flash floods in mountainous areas often have devastating debris flows. Also, most of the losses due tothe 1964 Alaska earthquake resulted from ground failure rather than fromshaking of structures, and landslides associated with a major earthquake inAfghanistan and with Hurricane Mitch in Central America in 1998 caused themajority of fatalities in these disasters.All 50 States and the U.S. Territories experience landslides and otherground-failure problems; 36 States have moderate to highly severe landslidehazards. The greatest landslide damage occurs in the Appalachian, RockyMountain, and Pacific Coast regions and Puerto Rico. Seismically activemountainous regions, such as those in Alaska, Hawaii, and the West Coast areespecially at risk. Extremely vulnerable are areas where wildfires havedestroyed vegetation, exposing barren ground to heavy rainfall.Landslide losses are increasing in the United States and worldwide asdevelopment expands under pressures of increasing populations. The resultingencroachment of developments into hazardous areas, expansion of transportation infrastructure, deforestation of landslide-prone areas, and changing climate patterns may lead to continually increasing landslide losses. However, anincrease in the cost of landslide hazards can be curbed through better understanding and mapping of the hazards and improved capabilities to mitigate andrespond to the hazards.7Highlight 2—Wildfires and Debris FlowsDuring the summer of 2000,numerous wildfires burned droughtparched areas of the Western UnitedStates. U.S. Geological Survey (USGS)scientists were enlisted to adviseFederal and State emergencyresponse teams on the potential forfuture debris flows in burned areas,such as the Cerro Grande fire (LosAlamos, New Mexico) and the HiMeadow and Bobcat fires (Colorado).Debris flows often occur duringthe fall and winter following majorsummer fires. One such combinationof fires and debris flows occurred inJuly 1994, when a severe wildfireswept Storm King Mountain west ofGlenwood Springs, Colorado, denuding the slopes of vegetation. Heavyrains on the mountain the followingSeptember caused numerous debrisflows, one of which blocked Interstate70 and threatened to dam theColorado River (fig. 2). A 3-mile lengthof the highway was buried under tonsof rock, mud, and burned trees. Theclosure of Interstate 70 imposed costly delays on this major transcontinental highway. The USGS assisted inanalyzing the debris-flow threat andinstalling monitoring and warning systems to alert local safety officialswhen high-intensity rainfall occurredor debris flows passed through a susceptible canyon. Similar debris flowsthreaten other transportation corridors and other development in andnear fire-ravaged hillsides.From Highland, L.M., Ellen, S.D.,Christian, S.B., and Brown, W.M., III,1997, Debris-flow hazards in theUnited States: U.S. Geological SurveyFact Sheet FS–176–97, available onthe web athttp://geohazards.cr.usgs.gov/factsheets/debrisflowfs.pdf.Figure 2. Debris flows like this one nearGlenwood Springs, Colorado, in 1994are a consequence of heavy rainfall onpreviously burned hillsides. In additionto personal injuries and damage to 30vehicles engulfed by these flows, transportation along the Interstate 70 corridor was brought to a standstill for a day,and business and emergency operations in the Glenwood Springs areawere seriously impeded. Photograph byJim Scheidt, U.S. Bureau of LandManagement.8Landslides and other ground failures impose many direct and indirectcosts on society. Direct costs include the actual damage sustained by buildingsand property, ranging from the expense of cleanup and repair to replacement.Indirect costs are harder to measure and include business disruption, loss oftax revenues, reduced property values, loss of productivity, losses in tourism,and losses from litigation. The indirect costs often exceed the direct costs.Much of the economic loss is borne by Federal, State, and local agencies thatare responsible for disaster assistance and highway maintenance and repair.Landslides have a significant adverse effect on infrastructure and threatentransportation corridors, fuel and energy conduits, and communications linkages. Ground-failure events have devastating economic effects on Federal,State, local, and private roads, bridges, and tunnels every year. Railroads,pipelines, electric and telecommunication lines, dams, offshore oil and gasproduction facilities, port facilities, and waste repositories continually areaffected by land movement. Road building and construction often exacerbatethe landslide problem in hilly areas by altering the landscape, slopes, anddrainages and by changing and channeling runoff, thereby increasing thepotential for landslides. Landslides and others forms of ground failure alsohave adverse environmental consequences, such as dramatically increased soilerosion, siltation of streams and reservoirs, blockage of stream drainages, andloss of valuable watershed, grazing, and timber lands.9Highlight 3—Building Disaster-ResistantCommunitiesAn outstanding example of public-private partnerships is the FederalEmergency Management Agency’s(FEMA) Disaster-Resistant Communitiesproject (formerly called ProjectImpact). Nearly 200 communities andmore than 1,100 business partnershave embraced this project since itsinception in 1997. Rather than waitingfor disasters to occur, communitiestake action to reduce potentially devastating disasters. Seattle Washington,a city that is exposed to significantlandslide hazards, was one of the firstcommunities in the United States tojoin.In conjunction with FEMA, thecity of Seattle collaborated with theU.S. Geological Survey (USGS) todevelop landslide hazard maps thatwill enable the city to be better prepared for landslide emergencies andto reduce losses resulting from landslide disasters (fig. 3). The city madeavailable information needed by USGSscientists to accurately assess landslide hazards in the area and to produce a computer-based landslide haz-ard map. This map includes Seattle'sdetailed topographic database andrelated geographic data, detailed precipitation data collected by theNational Weather Service, geographicinformation system support for completing the maps, and a landslidedatabase from city records that dateback to the late 1800s. USGS scientists are analyzing city data along withother information to determine thedegree of landslide hazard throughoutthe city. The scientists are also conducting studies to determine the probability that landslides will result fromstorms of different magnitudes.The Disaster-ResistantCommunities project has resulted inunprecedented awareness of landslide hazards by the private sector.For example, major mortgage bankershave realized that they hold mortgages on many properties in areas ofsignificant landslide hazard in Seattleand elsewhere in the United Statesand are beginning to take steps toencourage homeowners to mitigatethe hazards.Figure 3. Landslide in northwest Seattle,Washington. Foundation of the house onthe right edge of the photograph andthe decks of neighboring houses havebeen undermined. Photograph by AlanF. Chleborad, U.S. Geological Survey.10Society is far from helpless in the face of these prospects.Improvements in our scientific understanding of landslides and otherground-failure hazards can provide more accurate delineation of hazardousareas and assessments of their hazard potential. This information can bedeveloped in a form and at a scale meaningful and useful for decisionmaking. Cost-effective actions can be taken to reduce the loss of lives and property, damage to the environment, and economic and social disruptioncaused by landslides and other ground failures (see appendix 4 for moreinformation about mitigation techniques).Government at all levels plays critical roles in advancing landslidehazard mitigation and developing programs and incentives that encourageand support community-based implementation. A national strategy toreduce losses from landslides and other ground failures must have bothresearch and implementation components to increase understanding oflandslides and other ground failures and put existing knowledge to use toreduce losses. Developing durable and comprehensive solutions to landslidesand other ground-failure hazards will require a continuing dialog amongand concerted action by all sectors of our society.A new public-private partnership is needed at the Federal, State, andlocal levels to foster continuing cooperation among geologists, engineers,hydrologists, planners, and decisionmakers regarding landslides and othernatural hazards. This ongoing effort will, over time, help to ensure that theneeded scientific and engineering information is developed in a form usefulfor planning and decisionmaking and that such information is applied tomitigate these hazards.A National Strategy11Highlight 4—Debris-Flow Flume—Understanding LandslideProcessesU.S. Geological Survey (USGS)and U.S. Forest Service (USFS) scientists recreate debris flows in a flumethat has been constructed to conductcontrolled experiments (fig. 4).Located about 45 miles east ofEugene, Oregon, this unique facilityprovides research opportunities available nowhere else in the UnitedStates. USGS and USFS scientistsconduct experiments to improve theunderstanding of ground vibrationscaused by debris flows and to refineautomated debris-flow detection systems. The flume also provides anideal environment for testing landslidecontrols that deflect, trap, or channelize debris flows. Experiments thatassess how debris flows react to andact upon such controls can be usedto guide and evaluate engineeringdesigns.The debris-flow flume is a reinforced concrete channel 310 feetlong, 6.6 feet wide, and 4 feet deepthat slopes 31 degrees, an angle typical of terrain where natural debrisflows originate. Removable glass windows built into the side of the flumeallow flows to be observed and photographed as they sweep past. A totalof 18 data-collection ports in the floorFigure 4. The U.S. Geological Survey(USGS) debris-flow flume is located inH.J. Andrews Experimental Forest,Oregon. The flume was constructed toconduct controlled debris-flow experiments. Photograph courtesy of theUSGS, taken September 13, 2001.12of the flume permit measurements offorces due to particles sliding andcolliding at the based of flows.Additional insight can be gained byusing ultrasound imaging to "see"into the interior of flows and bydeploying "smart rocks" containingminiature computers that record therocks’ accelerations as they movedown the flume.To create a debris flow, 20 cubicmeters (about 40 tons) of saturatedsediment are placed behind a steelgate at the head of the flume and thenreleased. Alternatively, a slopingmass of sediment can be placedbehind a retaining wall at the flumehead and watered until slope failureoccurs. The ensuing debris flowdescends the flume and forms adeposit at the flume base. The flumedesign thus accommodates researchon all stages of the debris-flowprocess, from initiation throughdeposition.From Iverson, R.M., Costa, J.E., andLaHusen, R.G., 1982, Debris flowflume at H.J. Andrews ExperimentalForest, Oregon: U.S.Geological SurveyOpen-File Report 92–483, 2 p.The National Landslide Hazards Mitigation Strategy described hereinenvisions a society that is fully aware of landslide hazards and routinely takesaction to reduce both the risks and costs associated with those hazards. Thestrategy envisions bringing together relevant scientific, engineering, construction, planning, and policy capabilities of the Nation to eliminate losses fromlandslides and other ground-failure hazards nationwide.The long-term mission of such a strategy is to provide and encourage theuse of scientific information, maps, methodology, and guidance for emergencymanagement, land-use planning, and development and implementation of public and private policy to reduce losses from landslides and other ground-failurehazards nationwide.The NationalLandslide HazardsMitigation StrategyThe strategic plan described in this report has nine major elements, spanning a continuum from research to the formulation and implementation of policy and mitigation objectives. Implementation of such a strategy will demand amultiyear coordinated public and private effort. All levels of government andthe private sector share responsibility for addressing these priorities andaccomplishing the objectives. Some of the objectives consist of a single, discrete action; others encompass a series of interdependent actions to be takenover the first 10 years of implementation. Although the primary focus is onlandslide hazards, the national strategy provides a framework for addressingother forms of ground failure as well.The USGS has a role in each of the nine elements as a provider of landslide hazard information; however, the lead and participants in each elementdiffer with the nature of the element.Reaching the Goal13Major Elements andStrategic ObjectivesElement 1. ResearchResearch to develop a predictive understanding of landslide processes andtriggering mechanisms will be led by the USGS. Hazard identification is acornerstone of landslide hazard mitigation. Although many aspects of landslide hazards are well understood, a much more comprehensive understandingof landslide processes and mechanisms is required to truly advance our abilityto predict the behavior of differing types of landslides. The following actionswill increase the Nation’s capability to forecast landslide hazards throughenhanced research, the application of new technology, and an increased understanding of landslide processes, thresholds, and triggering mechanisms:•••Element 2. HazardMapping andAssessmentsEfforts to delineate susceptible areas and different types of landslide hazards at a scale useful for planning and decisionmaking will be led by theUSGS and State Geological Surveys. Landslide inventory and landslide susceptibility maps are critically needed in landslide-prone regions of the Nation.These maps must be sufficiently detailed to support mitigation action at thelocal level. To cope with the many uncertainties involved in landslide hazards,probabilistic methods are being developed to map and assess landslide hazards(see appendix 5 for more information about mapping and assessing landslidehazards). Risk assessments estimate the potential economic impact of landslide hazard events. Landslide inventory and susceptibility maps and otherdata are a critical first step and are prerequisite to producing probabilistic hazard maps and risk assessments, but these maps and data are not yet availablefor most areas of the United States. The following actions will provide thenecessary maps and assessments and other information to officials andplanners to reduce risk and losses:•••14Develop a national research agenda and a multiyear implementationplan based on the current state of scientific knowledge concerninglandslide hazard processes, thresholds, and triggers and on the ability to predict landslide hazard behaviorDevelop improved, more realistic scientific models of ground deformation and slope failure processes and implement their use in predictinglandslide hazards nationwideDevelop dynamic landslide prediction systems capable of interactivelydisplaying changing landslide hazards in both space and time in areasprone to different types of landslide hazards (for example, shallowdebris flows during intense rain, deep-seated slides during months ofwet weather, and rock avalanches during an earthquake)Develop and implement a plan for mapping and assessing landslideand other ground-failure hazards nationwideDevelop an inventory of known landslide and other ground-failurehazards nationwideDevelop and encourage the use of standards and guidelines for landslide hazard maps and assessmentsA major landslide event occurredin Madison County, Virginia, in thesummer of 1995. During an intensestorm on June 27th, 30 inches of rainfell in 16 hours. In mountainous areas,rain-saturated landslides known asdebris flows were triggered by thehundreds, causing extensive devastation and one fatality.Historical records tell us thatdestructive landslides and debrisflows in the Appalachian Mountainsoccur when unusually heavy rain fromhurricanes and intense storms soaksthe ground, reducing the ability ofsteep slopes to resist the downslopepull of gravity. For example, duringHurricane Camille in 1969, such conditions generated debris flows inNelson County, Virginia, 90 milessouth of Madison County. The stormcaused 150 deaths, mostly attributedto debris flows, and more than $100million in property damage. Likewise,72 hours of storms in Virginia andWest Virginia during early November1985 caused debris flows and floodingin the Potomac and Cheat Riverbasins that were responsible for 70deaths and $1.3 billion in damage tohomes, businesses, roads, and farmlands.Scientists from the U.S.Geological Survey have developed aninventory of landslides, debris flows,and flooding from the storm of June27, 1995, by using aerial photography,field investigations, rainfall measurements from rain gages, and NationalWeather Service radar observations.This inventory and a new debris-flowhazard map (fig. 5) are being used tohelp understand the conditions thatled to the floods and debris flowscaused by the 1995 summer storms inVirginia and to suggest methods ofmitigating the effects of such eventsin the future.From Gori, P.L., and Burton, W.C., 1996,Debris-flow hazards in the Blue Ridgeof Virginia: U.S. Geological SurveyFact Sheet FS–159–96, 4 p.Highlight 5—Mapping Debris-Flow Hazardsin Madison County, VirginiaFigure 5. Portion of debris-flow hazardmap, Madison County, Virginia. FromMorgan, B.A., Wieczorek, G.F., andCampbell, R.H., 1999, Historical andpotential debris-flow and flood hazardmap of the area affected by the June27, 1995, storm in Madison County,Virginia: U.S. Geological SurveyGeologic Investigations Series MapI–2623–B, 1 sheet.15Element 3. Real-TimeMonitoringStudies to monitor active landslides that pose substantial risk will be ledby the USGS. Monitoring active landslides serves the dual purpose of providing hazard warning in time to avoid or lessen losses, as well as supportinglandslide research by providing new insights into landslide processes and triggering mechanisms. Collection of rare dynamic movement behavior dataenables the testing of landslide velocity models and the development ofimproved predictive tools applicable to other slides. Development and application of real-time monitoring of active landslides using state-of-the-art researchand telecommunications technologies are critically needed nationwide in casesof imminent risk. The following actions will provide the necessary warningand other information to officials and communities to avoid or reduce losses:•••••16Develop and implement a national landslide hazard monitoring andprediction capabilityDevelop real-time monitoring and prediction capabilities on both sitespecific and regional scales, to assist Federal, State, and local emergency managers determine the nature of landslide hazards and theextent of ongoing risksApply remote-sensing technologies such as Synthetic Aperture radarand laser altimetry for monitoring landslide movement nationwideIncorporate state-of-the-art techniques such as microseismicity andrainfall and pore-pressure monitoring with hydrologically based modelsof slope stability and global positioning systems (GPS)Integrate real-time monitoring capabilities with the National WeatherService’s NEXRAD capabilities in selected locations nationwideFive landslides that threaten U.S.Highway 50 and nearby homes inSierra Nevada, California, are beingmonitored by the U.S. Geological Survey (USGS) after heavy rains inJanuary 1997 generated debris flowsthat blocked Highway 50. The cost ofreopening the highway was $4.5 million, with indirect economic lossesfrom closure of the highway amounting to an additional $50 million. Tomonitor the risk posed by landslidesin this area, the USGS, in cooperationwith local, State, and other FederalAgencies, provides continuous realtime monitoring of landslide activityusing a system developed by theUSGS for monitoring active volcanoesin remote areas (fig. 6).This system measures groundmovement and ground-water pressures every second. Slope movementis recorded by instruments that detectstretching and shortening of theground (fig. 7). Ground vibrationscaused by slide movement are monitored by geophones buried within theslide. Ground-water conditions withinthe slides are monitored by sensors,and rain gauges record precipitation.Under normal conditions, data aretransmitted to USGS computers every10 minutes, but if strong ground vibrations caused by massive landslidemovement are detected, data aretransmitted immediately (fig. 8).The USGS operates other remotereal-time landslide monitoring sites.Near Seattle, Washington, a real-timesystem monitors a slide threatening amajor railway, and in Rio Nido,California, another system monitors alarge landslide threatening more than140 homes. Remote monitoring alsocan record the effects of wildfire indestabilizing slopes.From Reid, M.E., LaHusen, R.G., andEllis, W.L., 1999, Real-time monitoringof active landslides: U.S. GeologicalSurvey Fact Sheet FS–91–99, 2 p.Highlight 6—Real-Time Monitoring ofActive LandslidesFigure 6. Network for transmission ofreal-time landslide data.Figure 7. Measuring landslide movement.Photograph by Richard LaHusen, U.S.Geological Survey.Figure 8. Testing a solar-powered radiotelemetry system for remote transmissionof real-time landslide data. Photograph byMark Reid, U.S. Geological Survey.17Element 4. LossAssessmentA project compiling and evaluating information on the economic impactsof landslide hazards will be led by FEMA and the insurance industry.Although losses from landslides and other natural hazards are frequent andwidespread, these losses are not consistently compiled and tracked in theUnited States. Following a landslide or other natural hazard event, a variety ofdifferent agencies and organizations may provide damage estimates, but theseestimates usually vary widely, cover a range of different costs, and changethrough time. The National Research Council concluded in their 1999 report"The Impact of Natural Disasters—A Framework for Loss Estimation" thatthere is no widely accepted framework for estimating the losses from naturaldisasters, including landslide and other ground-failure hazards. This lack ofinformation makes it difficult to set policies for coping with these hazards anddifficult to gage the cost-effectiveness of policy decisions and effectiveness ofmitigation measures. Loss data are critically needed to help government agencies identify trends and track progress in reducing losses from landslides. Thefollowing actions will provide a framework for compiling and assessing acomprehensive data base of losses from landslides and other ground -failurehazards, which will help guide research, mapping, and mitigation activitiesnationwide:••18Assess the current status of data on losses from landslides and otherground failures nationwide, including the types and extent of losses topublic and private property, infrastructure, and natural and culturalresourcesEstablish and implement a national strategy for compilation, maintenance, and evaluation of data on the economic and environmentalimpacts of landslide and other ground-failure hazards nationwide tohelp guide mitigation activities and track progressThree significant PacificNorthwest storm events in February1996, November 1996, and lateDecember 1996 and early January1997 initiated widespread slope failures throughout Oregon. Each ofthese storms was declared a "MajorPresidential Disaster Declaration,"and damages to natural resourcesand infrastructure were extreme. Inthe Portland metropolitan region,Oregon’s largest city, more than 700slope failures were associated withthe heavy rains in 1996, with 17houses completely destroyed and 64partially condemned. An estimate ofstatewide public and private damagesincurred from the February 1996 eventalone is $280 million.To better characterize the distribution and magnitude of the slopefailures associated with the threestorms, the Federal EmergencyManagement Agency provided funding for the consolidation of a landslideinventory (fig. 9). The OregonDepartment of Geology and MineralIndustries led the consolidation effortand utilized various methods to contact potential data sources, informthem of the existence of the study,and request their participation. Thisinventory will help lead to a greaterunderstanding of regional landslideissues and assist government andcommunity agencies in devisingmeans to minimize the threat to publichealth and property that landslidespose.Over 9,000 landslide locationswere incorporated into the inventory,with varying amounts of informationreported for each. Many other slideswere not observed or recorded, and itis estimated that two to three timesthis many landslides occurred duringthe time period. As shown on thelandslide inventory map, the vastmajority (98 percent) of the entriesare in the western portion of theState. Most of these slides occurredin the Oregon Coast Range and Cascade province, with fewer in theWillamette Valley and Klamath Mountains.Highlight 7—Inventory of Slope Failures inOregon for Three 1996–97Storm EventsFrom Hofmeister, R.J., 2000, Databaseof slope failures in Oregon for three1996/97 storm events: OregonDepartment of Geology and MineralIndustries.Figure 9. Landslide inventory for three1996–97 storm events in Oregon.19The effort to establish an effective system for information transfer willElement 5. InformationCollection, Interpretation, be led by the USGS and State Geological Surveys. Collecting and disseminating landslide hazards information to Federal, State, and local governmentDissemination, andagencies; nongovernmental organizations; planners; policymakers; and priArchivingvate citizens in a form useful for planning and decisionmaking are criticallyimportant to an effective mitigation program. Although landslide hazardshave been studied for decades, a systematic effort to collect and distributescientific and technical information is in its relative infancy. The USGSNational Landslide Information Center is a prototype system that can beenhanced and extended into a robust nationwide system for the collection,interpretation, and dissemination of landslide hazard maps, assessments, andother scientific and landslide hazard technical information. The followingobjectives will make landslide hazard information accessible to scientists,officials, decisionmakers, and the public to assist research, planning, policy,and mitigation activities:••20Evaluate and use state-of-the-art technologies and methodologies forthe dissemination of technical information, research results, maps, andreal-time warnings of potential landslide activityDevelop and implement a national strategy for the systematic collection, interpretation, archiving, and distribution of this informationAn experimental monitoring andwarning system was developed andoperated jointly by the U.S. GeologicalSurvey (USGS) and the NationalWeather Service (NWS) from the1980s to 1995 in the San FranciscoBay region (fig. 10). The system used(1) NWS protocols and outlets forissuing warnings and (2) regional networks of NWS and USGS rain gagesand soil-moisture instruments to trackrainfall and soil-moisture conditions.Rainfall thresholds for triggering landslides were determined on the basisof observed relationships betweenrainfall intensity and duration and theoccurrence of landslides. When realtime data and high precision forecasting by the NWS indicated that therainfall threshold for landslides had orwould soon be reached, USGS scientists informed the NWS to issue awarning through normal media channels. The media, government officials,and the general public in the bay areacame to rely on these warnings andtook specific actions such as evacuating neighborhoods at particular risk.Under the National LandslideHazards Mitigation Strategy, next-generation landslide warning systems willbe implemented in landslide-proneregions nationwide. Precipitation, soilmoisture, and pore-pressure data willtelemetered in real time to networkcenters for processing and analysis.These measurements will help definethe precipitation thresholds and supplement the NWS NEXRAD (NextGeneration Radar) network and otherprecipitation data and forecasts provided by the NWS or local agencies.Warnings of potential landslide activity that might be triggered by storms orextended rainy periods will be issuedin cooperation with the NWS andFederal and State emergency management agencies.Figure 10. Debris flow from a steep hillslope in Pacifica, California, about 10 miles southof San Francisco, where three children were killed and two homes destroyed on January4, 1982. Inset, View of destroyed homes from the street. Photograph by Gerald Wieczorek,U.S. Geological Survey. From U.S. Geological Survey, 1995, Debris-flow hazards in theSan Francisco Bay region: U.S. Geological Survey Fact Sheet FS–112–95, 2 p. Availableon the web at http://greenwood.cr.usgs.gov/pub/fact-sheets/fs-0112-95/.Highlight 8—Warning of PotentialLandslides21Efforts to develop guidelines and training for scientists, engineers, and deciElement 6. Guidelines andsionmakerswill be led by the USGS and professional societies. The study ofTraininglandslide hazards is an area of active research and technological application, andthere is a critical need for guidelines and training for scientists and engineers in thedevelopment of landslide maps and assessments. Hazard assessments involveassumptions and calculations about the magnitude and return frequency in specificgeographic settings. Risk assessments involve assumptions about the potentialphysical and economic impacts of landslide hazard events. The development andpresentation of the results in terms that are useful to citizens and decisionmakersare critically important to effective mitigation. Likewise, development of guidelinesand training for planners and other decisionmakers in the use of these maps andassessments are important to encouraging its appropriate use by the user community.The following are high priority objectives related to guidelines and training:•••Element 7. PublicAwareness andEducationEfforts to develop information and education programs for the user community will be led by FEMA and the USGS. Before individuals and communities can reduce their risk from landslide hazards, they need to know the natureof the threat, its potential impact on them and their community, their optionsfor reducing the risk or impact, and methods for carrying out specific mitigation measures. Achieving widespread public awareness of landslide hazardswill enable communities and individuals to make informed decisions on whereto live, purchase property, or locate a business. Local decisionmakers willknow where to permit construction of residences, business, and critical facilities to reduce potential damage from landslide hazards. The following actionswill raise public awareness of landslide hazards and encourage landslide hazardpreparedness and mitigation activities nationwide, tailored to local needs:•••22Develop and implement guidelines and training for scientists and geotechnical engineers in the use of landslide hazard and other technicalinformation for mapping and assessing landslide hazardsDevelop and implement guidelines and training for scientists and geotechnical engineers for responding to landslide disasters and providingneeded scientific and technical information for response and recoveryeffortsDevelop and implement guidelines and training for planners and decisionmakers in the use of landslide hazard maps, assessments, and othertechnical information for planning, preparedness, and mitigationDevelop public awareness, training, and education programs involvingland-use planning, design, landslide hazard curriculums, landslide hazard safety programs, and community risk reductionEvaluate the effectiveness of different methods, messages, and curriculums in the context of local needsDisseminate landslide-hazard-related curriculums and training modulesto community organizations, universities, and professional societiesand associationsMount Rainier in WashingtonState is an active volcano that is currently at rest between eruptions. Itsnext eruption may produce volcanicash, lava flows, or pyroclastic flows(fig. 11). Pyroclastic flows are hotavalanches of lava fragments and gasformed by volcanic eruptions.Pyroclastic flows can rapidly meltsnow and ice, and the resulting meltwater torrent may produce lahars (thewidely used Indonesian word for volcanic mudflows and debris flows) thattravel down valleys beyond the baseof the volcano. Lahars may also occurduring noneruptive times when a section of the volcano collapses.Lahars look and behave likerapidly flowing concrete, and theirimpact can destroy most manmadestructures. Historically at MountRainier, they have traveled 45–50miles per hour in thicknesses of 100feet or more in confined valleys, slowing and thinning as they flowed intowider valleys, most of which are populated. At Mount Rainier, lahars posea greater risk than other volcanichazards, such as lava and poisonousgases.The likely courses of lahars arethe river valleys that drain MountRainier. Four of the five major riversystems flow westward into suburbanareas of Pierce County. The U.S.Geological Survey mapped the likelyflow pathways and has joined withlocal, county, and State agencies todevelop a Mount Rainier hazards planthat will address such issues asemergency response operations andstrategies for expanded publicawareness and mitigation.From Scott, K.M., Wolfe, E.W., andDriedger, C.L., 1998, Mount Rainier;living with perilous beauty: U.S.Geological Survey Fact SheetFS–065–97, 4 p. and Hoblitt, R.P.,Walder, J.S., Driedger, C.L., Scott,K.M., Pringle, P.T., and Vallance, J.W.,1998 (rev.), Volcano hazards fromMount Rainier, Washington: U.S.Geological Survey Open-File Report98–428, 11 p., 2 oversize sheets.Figure 11. Hazard zones from lahars, lava flows, and pyroclastic flows from MountRainier. From Scott, K.M., Wolfe, E.W., and Driedger, C.L., 1998, Mount Rainier; livingwith perilous beauty: U.S. Geological Survey Fact Sheet FS–065–97, 4 p.Highlight 9—Alerting the Public to theHazards of Mount Rainier23Element 8.Implementation of LossReduction MeasuresEfforts to encourage mitigation action will be led by FEMA, Statedepartments of emergency services, and professional societies. A successfulstrategy for reducing landslide losses must also include a mitigation component. Mitigation actions generally fall to State and local governments, businesses, and individuals. As a result, societal attitudes and perceptions canpresent formidable obstacles to landslide hazards reduction. Few communities have considered the full range of mitigation options despite their feasibility and cost effectiveness. Mitigation measures at the local level includea range of tools and techniques, such as land-use planning, regulation ofdevelopment, engineering controls, building codes, assessment districts,emergency planning and warning, and private financial and insurance incentives and disincentives. The following actions will facilitate and encourageimplementation of appropriate and effective mitigation measures that aretailored to local needs:•••••24Evaluate impediments to effective planning and controls on development and identify approaches for removing those impediments.Develop an education program for State and local elected and appointed officials that sensitizes them to the risk and costs of landslide hazards and encourages them to develop legislation and policies that support effective landslide hazard mitigationDevelop and disseminate prototype incentives and disincentives forencouraging landslide mitigation to government agencies, the privatesector, and academiaEvaluate engineering and construction approaches to mitigate landslidehazards and develop a national plan for research to improve these techniquesEncourage implementation of successful landslide mitigationtechnologiesLandslides are a significant problem in several areas of Ohio, andCincinnati has one of the highest percapita costs due to landslide damageof any city in the United States.Landslides have been known to occurin the Cincinnati area in southwesternOhio and the adjoining States ofKentucky and Indiana since beforethe 1850s, but the damage caused bylandslides has become increasinglyexpensive as urban developmentencroaches more and more on thearea’s hillsides. The city of Cincinnatispent an average of $550,000 per yearon emergency street repairs for damage due to landslides between 1983and 1987 (fig. 12).In 1974, the Cincinnati CityCouncil passed an excavation and fillordinance to help reduce landslidedamage in areas of new construction.In 1989, Cincinnati created a geotechnical office within its Departmentof Public Works. The office, which isstaffed by a geotechnical engineer, anengineering geologist, and two technicians, carries out a mitigation program. Since 1989, members of thegeotechnical staff have worked inseveral ways to reduce landslidedamage in the city; their workincludes engineering geologic mapping of selected parts of the city,inspecting retaining walls that affectpublic right-of-way, reviewing proposed construction in hillside areas,inspecting and arranging for repair oflandslide areas that affect city property, and compiling geologic andgeotechnical data on landslide areaswithin the city. In 1990, HamiltonCounty also adopted an excavationand fill ordinance to help reduce thedamage due to landslides in areas ofnew construction.From Hansen, M.C., 1995, Geofacts:Ohio Department of NaturalResources, no. 8 and Baum, R.L., andJohnson, A.M., 1996, Overview oflandslide problems, research, andmitigation, Cincinnati, Ohio, area: U.S.Geological Survey Bulletin 2059–A,p. A1–A33.Highlight 10—Cincinnati, Ohio—A Leaderin Landslide Loss ReductionMeasuresFigure 12. Earthflow material beingremoved by a highway crew along theColumbia Parkway, Cincinnati, Ohio. Hamilton County, in the metropolitan Cincinnatiarea, experienced an average annual economic loss of $5.80 per person (1975 dollars)between 1973 and 1978, the highest calculated per capita loss of any municipality in theUnited States. Photograph courtesy of theU.S. Geological Survey.25Element 9. EmergencyPreparedness,Response, andRecoveryEfforts to develop resilient communities will be led by FEMA and Statedepartments of emergency services. Despite improved landslide hazard mitigation, disasters will occur. For this reason, governments at all levels, the privatesector, and the public will need to be able to adequately prepare for, respondto, and recover from disasters involving landslides. Governments will need tobetter plan for landslide emergencies. Scientists, engineers, and emergencyresponse professionals will need to be trained in the best practices to employduring a response, and public officials responsible for recovery from disasterswill need to be informed of options that will reduce future landslide losses.Incorporating the following actions in a national landslide mitigation strategywill improve the Nation’s ability to respond to and recover from landslide disasters:•••26Provide training for Federal, State, and local emergency managers onlandslide hazards preparedness, response, and recoveryDevelop a coordinated landslide rapid response capability to assistlocal, State, and Federal emergency managers in determining thenature of landslide hazards and the extent of ongoing risksProvide dedicated landslide expertise and equipment required for rapidemergency deployment of real-time data to emergency managers, aswell as the ability to successfully transfer monitoring technology toother agenciesActive landslides pose an increasing problem to older communities. Anexample of this dilemma came to ahead in April 2000, when 21 late-1950sera homes in Daly City, California,were condemned because of continued landsliding along Westline Drive.The homes were deemed permanentlyuninhabitable, and the city had nochoice but to remove their inhabitantsfrom imminent danger. By May, all residents had moved.The Westline Drive landslide firstcame to the attention of Daly City residents in 1966, when sliding forcedthe removal of homes from a subdivision developed just 7 years earlier.One more home was removed in 1980.The movement lessened until the ElNiño winter of 1997–98, one of thewettest rainy seasons on record,caused the landslide to reactivate(fig. 13). As a result, Westline Drivedropped as much as 4 feet in someareas.The decision by the city to condemn the houses was in reaction tothe local gas utility’s decision to shutoff gas service in February to theaffected area of Westline drive afterfinding numerous irreparable leaks.The utility feared that pipe ruptureswould cause an explosion. In addition, the city closed off the street totraffic, including garbage and emergency vehicles, after discovering a10-foot-square cavity beneath thepavement.Assisting the homeowners was achallenge because no insurance wasavailable. The Federal EmergencyManagement Agency offered to buythe homes, but funds covered onlypart of the previous value of thehomes. The Federal Small BusinessAdministration offered mortgageloans at 4 percent, but only for areduced value of the homes, and thehomeowners had to pay off theirexisting mortgages. Daly City and SanMateo County planned to supplementthe Federal Government’s $6.5 millionoffer of assistance with housingfunds totaling $1 million. Daly Cityplanned to take over the deeds fromthe homeowners and turn the landinto open space.Highlight 11—Daly City—The Human Costof LandslidesFrom San Francisco Chronicle,March 30 and May 2, 2000, AngelicaPence, staff writer, and RussellGraymer, U.S. Geological Survey.Figure 13. Gully retreat threatening evacuated houses in Daly City, a suburb of SanFrancisco, California, following the storm ofFebruary 2–3, 1998. Landslide and mudslideactivity was extensively reported in the newsmedia following heavy rains on February 2–3,1998. A number of scattered, slow-movinglandslides had been active over the weeksprior to the storm in San Francisco, Oakland,and elsewhere in the San Francisco Bayregion. As most of the area experiencedabout 200 percent of normal rainfall in thewinter of 1998, these landslides were probably related more to the wet winter and less tothe effects of this particular storm. However,based on limited ground reconnaissance,scattered slope movements directly relatedto the storm did occur. Debris flows directlytriggered by the storm affected a number ofhomes and properties. From U.S. GeologicalSurvey web site http://landslides.usgs.gov/html_files/landslides/reconrpt.html, 1998,accessed July 29, 2002. Photograph bySteve Ellen, U.S. Geological Survey.27Action Items for aNational Strategyfor ReducingLosses fromLandslidesLandslide hazard mitigation necessitates interactive collaboration amongacademia, industry, government, and the private sector. The following keyaspects of a National Landslide Mitigation Strategy will allow for rapid andsignificant progress toward a sustained mitigation of landslide hazards nationwide:Key Steps forImplementation••••Management PlanDurable and effective solutions to the Nation’s ground-failure-hazardproblems will require a continuing dialog among and concerted action by allsectors of our society. An effective National Landslide Hazards MitigationStrategy will require a combination of purposeful management to ensurecoordination and consortium-type decisionmaking to accommodate the multijurisdictional, cooperative nature of the program. An effective managementplan will include the following:•••New and EnhancedRoles and Partnerships28Conduct Federal-State and public-private forums to establish regionalpriorities for research, mapping, monitoring, forecasting, and mitigating landslide hazardsEstablish new and enhance existing programs to fund research, mapping, monitoring, and mitigation activities nationwideDevelop Federal-State and public-private programs to delineate landslide prone areas, to forecast the potential for landslides, and to mitigate lossesEstablish and enhance Federal-State and public-private partnerships toleverage and maximize relevant resources and expertiseEstablish coordination of the National Landslide Hazards MitigationStrategy under the leadership of the USGS, using the bureau’s expertise and experience in landslide hazards research, monitoring, mappingand data collection, analysis, archiving, and disseminationEstablish working groups with representatives of Federal, State, andlocal governments, academia, and private industry to help coordinateand guide the National Landslide Hazards Mitigation StrategyEstablish Federal-State public-private cooperative programs to fundand encourage landslide hazard research, mapping, assessment, andmitigation efforts nationwideMany Federal, State, and local agencies; academia; and private companiesare involved in landslide research and mitigation in the United States (seeappendixes 6 and 7 for more information about Federal, State, and local programs). A National Landslide Hazards Mitigation Strategy offers new opportunities for mutually advantageous partnerships relating to hazard assessments,monitoring, and emergency response and recovery.The national strategy enhances the ability of Federal, State and localagencies to partner effectively with the academic and the private sectors and toleverage shared resources. Table 1 outlines the complementary and supportiveroles and opportunities for new partnerships for each participant in theNational Landslide Hazards Mitigation Strategy.29A much more comprehensiveunderstanding of landslideprocesses and mechanisms isrequired to advance our abilityto predict the behavior ofdifferent types of landslides.Landslide inventory andlandslide susceptibility mapsare critically needed in manylandslide-prone regions of theNation. In general, there areno standards for mapping andassessments.Real-time monitoring ofactive landslides is criticallyneeded nationwide.Losses are not consistentlycompiled and tracked in theUnited States.There is no systematicnationwide collection ordistribution of landslidehazards information.2. Hazard Mapping andAssessments.—Delineating susceptibleareas and different typesof landslide hazards ata scale useful for planningand decisionmaking3. Real-TimeMonitoring.—Monitoring activelandslides that posesubstantial risk4. Loss Assessment.—Compiling and evaluatinginformation on theeconomic and environmental impacts of landslide hazards.5. InformationCollection,Interpretation,Dissemination, andArchiving.—Establishing aneffective systemfor information transferCurrentstatus1. Research.—Developing a predictiveunderstanding oflandslide processes andtriggering mechanismsElementStateLocalPrivateAcademicCollect and distribute neededinformation to decisionmakersCompile and share records of lossesDevelop robust landslide hazardsinformation clearinghouse systemfor the systematic collection,interpretation, archiving, anddistribution of scientific andtechnical information, data bases,and mapsEstablish and implementa national strategyfor compilation,maintenance, andevaluation of dataMonitor landslides and establish landslide warning systemsImprove real-time monitoring capabilitiesDevelop and shareinformationUse landslide hazard maps and assessments in planning, preparedness, and mitigationEstablish mapping andassessment standardsMap and assess landslide hazardsMap landslideson Federal landsUse results of research in policy, planning, and mitigation decisionsConduct researchCoordinate research prioritiesFederalNew roles and partnership opportunitiesTable 1. New roles and partnership opportunities under the National Landslide Hazards Mitigation Strategy.30There is a critical need forguidelines and training forscientists, engineers, planners,and decisionmakers.There is little public awarenessand understanding of landslidehazards, impacts on communities,or options for reducing risk.Mitigation necessarily occursat the local level; therefore,implementation of lossreduction measures variesfrom community to community.Federal, State, and localgovernments; theprivate sector; andthe public need to be able toadequately prepare, respond to,and recover from landslideemergencies.7. Public Awarenessand Education.—Developing informationand education programsfor the user community8. Implementation ofLoss ReductionMeasures.—Encouraging mitigationaction9. EmergencyPreparedness, Response,and Recovery.—Developing resilientcommunitiesCurrentstatus6. Guidelines andTraining.—Developing guidelinesand training forscientists, engineers,and decisionmakersElementLocalPrivateParticipate in training programsDevelop and implement guidelines and training curriculumsStateAcademicProvide training for Federal,State, and local emergencymanagersDevelop a coordinated landsliderapid response capability,including landslide hazardsexpertise and equipmentrequired for rapid emergencydeployment of real-time datato emergency managersDevelop and encourage policiesthat support landslide hazardmitigationDevelop financial incentivesand disincentives thatsupport landslide hazardmitigationDevelop and encourageengineering and constructionapproaches to mitigatelandslide hazardsProvide expertise during emergenciesImplement policiesthat reduce futurelandslide lossesEffectively respond to landslideemergenciesParticipatein trainingServe as consultants and advisorsAdopt and implement policiesand practices that supportlandslide hazardsmitigationDevelop and implement public awareness and education programs, involving land-useplanning, design, and landslide hazard curriculums; landslide hazard safetyand community risk reductionFederalNew roles and partnership opportunitiesTable 1. New roles and partnership opportunities under the National Landslide Hazards Mitigation Strategy.—ContinuedImplementation of the National Landslide Hazards Mitigation Strategywithin the USGS Landslide Hazards Program (LHP) will involve fourprincipal tasks—••••Expansion of work performed by scientists in the Landslide HazardsProgramEstablishment of new Cooperative Landslide Hazard Assessment andMapping ProgramEstablishment of a new Cooperative Federal Land ManagementLandslide Hazards ProgramEstablishment of new partnerships for the Landslide Hazard LossReduction ProgramFunding for theUSGS to Implementa National Strategyfor ReducingLosses fromLandslidesThe USGS Landslide Hazard Program is currently funded for $2.26 million in FY 2002. The changes above will require expansion of and additionalfunding for the LHP.Expanding efforts by USGS scientists in the areas of research, hazardassessment, monitoring, public information, and response will be necessaryto meet the challenges of the national strategy. The Landslide HazardsProgram will also require additional funding to meet new responsibilities tocoordinate activities within the Federal Government to fully implement thestrategy. Approximately $8 million in new funding will be required to supportthe following:••••••Expansion of the WorkPerformed by Scientistsin the LandslideHazards ProgramAdditional research on landslide processes and triggering mechanisms(element 1) ($1.5 million)Additional hazard maps and assessments of landslide-susceptible areas,including developing standards and guidelines (element 2) ($2 million)Additional monitoring of active landslides and improvement of stateof-the-art research and telecommunications technology (element 3)($2 million)Improved information collection, interpretation, dissemination, andtechnology transfer, including public awareness programs and education (elements 5 and 7) ($1 million)Expanded emergency response and recovery capability and activities(element 9) ($1 million)Coordination of National Landslide Hazard Mitigation Strategy ($0.5million)A new cooperative program will be established to encourage the understanding and mitigation of landslide and other ground-failure hazards byStates, Territories, counties, and other local jurisdictions. The program will beadministered by the USGS Landslide Hazards Program. The primary goal ofthis cooperative program will be to reduce hazard losses by increasing theavailability of assessments and maps of landslide- and other ground-failureprone areas in the United States. This program will address all elements of theEstablishment of a NewCooperative LandslideHazard Assessment andMapping Program31national strategy, with a primary focus on element 2, landslide hazard mappingand assessments. The USGS will provide guidance to encourage standardizedassessment and map products that will be available digitally.Priorities will be determined annually in consultation with State andTerritory representatives. Grants to States and Territories will be awardedcompetitively. States and Territories will determine priorities and the size ofgrants to be distributed to their local jurisdictions in consultation withStatewide and Territorywide advisory committees.Approximately $8.0 million will be required to support competitive grantsto the States, Territories, and local jurisdictions each year. Each grant will bematched by a 30 percent State or Territory contribution to encourage thedevelopment and use of landslide information in planning and mitigationactions at the State and local levels. It is anticipated that all States andTerritories will participate in such a program and that grants will average$150,000 per State or Territory.Establishment of a NewCooperative FederalLand ManagementLandslide HazardsProgram32A new program, administered by the USGS Landslide Hazards Program,will be established to increase and encourage the understanding and mitigationof landslide hazards on Federal lands, including assessment and mapping oflandslides, land-use planning and facility siting, emergency management, andpublic education.The goal of such a program will be to reduce losses from landslide andother ground-failure hazards through more informed and, therefore, betterstewardship of Federal lands under the jurisdiction of the National ParkService, the Bureau of Land Management, the Bureau of Reclamation, theBureau of Indian Affairs, and the U.S. Forest Service. The new program willaddress all elements of the national strategy, with a primary focus on landslidehazard mapping, assessments, and monitoring (elements 2 and 3).Priorities for scientific and technical assistance for Federal land management agencies will be determined annually in consultation with representativesof Federal land management agencies. Approximately $2.0 million will berequired for scientific and technical assistance for Federal land managementagencies. It is anticipated that the program will support approximately 20agreements, averaging $100,000 each. Most of these funds will be used tosupport hazard assessments and procure monitoring equipment, with USGSstaff providing technical assistanceA new competitive external grants program, administered by the USGSLandslide Hazards Program, will be established for research and implementation efforts. The program will foster partnerships with universities, privateconsulting firms, professional associations, Federally recognized Indian TribalGovernments, States and Territories, and local agencies. This program willaddress all elements of the strategy, with a primary focus on landslide hazardresearch and development and application of mitigation measures (elements 1,2, and 8).Priorities for research and application of research will be determinedannually in consultation with Federal, State, Territory, local, and privaterepresentatives. Approximately $2.0 million will be required for cooperativeagreements with universities, private consulting firms, professional associations,Federally recognized Indian Tribal Governments, States and Territories, andlocal agencies to support research and innovative application of research. Itis anticipated that the program will support approximately 25 agreements,averaging $80,000 each.Establishment of NewPartnerships forLandslide Hazard LossReduction ProgramTotal new funding to support implementation of a National LandslideHazard Mitigation Strategy is estimated to be $20 million annually, asfollows:Funding Summary••••Expansion of the research, assessment, monitoring, public information,and response efforts by USGS scientists ($8 million annually)Establishment of a Cooperative Landslide Hazard Assessment andMapping Program to increase the efforts of State and local governments to map and assess landslide hazards within their jurisdictionsthrough competitive grants ($8 million annually, to be augmented with30 percent matching funds by States and local jurisdictions)Establishment of a Cooperative Federal Land Management LandslideHazard Program to increase the capability of the National ParkService, U.S. Forest Service, Bureau of Land Management, andother such organizations to address landslide hazards under their jurisdictions ($2 million annually for work performed by USGS scientistson public lands)Establishment of a Partnerships for Landslide Hazard Loss ReductionProgram to support research and implementation efforts by universities,local governments, and the private sector through competitive grants($2 million annually)33MajorAccomplishmentsand ProductsFull implementation of the National Landslide Hazards MitigationStrategy will result in a number of major accomplishments and productsover the first 10 years of the program, including the following:••••••••••••••Reduced losses from landslidesReduced risk from future landslidesGreater public awareness of landslide hazards and options for mitigating lossesImproved technology for landslide mitigationAssessments and maps of landslide susceptibility in landslide-proneareasAssessments and maps of other ground-failure hazards in susceptibleareasAssessments and maps of landslide and ground-failure susceptibilityon Federal LandsPolicies to encourage landslide mitigation by government, communities, and the private sectorRobust national landslide hazards information clearinghouse systemData bases of economic and environmental losses from landslides andother forms of ground failures nationwideGuidelines and training materials for scientists, engineers, planners,decisionmakersCurriculums and training materials for public awareness of landslidehazardsReal-time monitoring of critically hazardous active landslides nationwideCoordinated landslide emergency response capability nationwideProgress in implementing the National Landslides Hazards MitigationStrategy will be monitored by working groups established to coordinate andguide the strategy. These groups will include representatives of Federal, State,and local governments and the private sector. Specific performance goals forthe strategy, including accomplishments and products, will come from a comprehensive review of national needs and priorities and will result in specificplans and schedules. In addition, progress in reducing losses will be monitoredas part of element 4— compilation and evaluation of losses from landslidehazards.Acknowledgments34This report is based on an early draft by Randall Updike of the USGS andon the ideas and suggestions from landslide hazard experts and others whoattended five stakeholder meetings. The report benefited from contributionsfrom and reviews by numerous USGS scientists and other Federal and Stateagency representatives. The authors would especially like to thank theAmerican Association of State Geologists for their thoughtful input andreview of the report.Appendix 1. Previous Reports and Sources ofLandslide Hazards InformationThe proposed National Landslide Hazards Mitigation Strategy incorporatesmany ideas and recommendations of previous studies and reports. The followingstudies and reports should be referred to for more in-depth discussions of andinsights into landslide hazard mitigation and research needs.U.S. Geological Survey Open-File Report 81–987, Goals, Strategies, Priorities andTasks of a National Landslide Hazard Loss Reduction Program (USGS, 1981),sets forth goals and tasks for landslide studies, evaluating and mapping ahazard, disseminating information, and evaluating the use of the information.U.S. Geological Survey Circular 880, Goals and Tasks of the Landslide Part of aGround-Failure Hazards Reduction Program (USGS, 1982), describes anational program.U.S. Geological Survey Open-File Report 85–276, Feasibility of a NationwideProgram for the Identification and Delineation of Hazards from Mud Flowsand Other Landslides (Campbell and others, 1985), identifies the need for anational program.Reducing Losses from Landsliding in the United States (Committee on GroundFailure Hazards, National Research Council, 1985, National Academy Press)recommends development of a national program and summarizes the roles ofgovernment and the private sector in landslide mitigation nationwide.U.S. Geological Survey Open File-Report 85–276–A, Landslide Classificationfor Identification of Mud Flows and other Landslides (Campbell and others,1985), resulted from a joint study by the USGS and FEMA to evaluate thefeasibility of delineating landslide hazards nationwide.Landslides Investigation and Mitigation, Special Report 247 (TransportationResearch Board, National Research Council, 1996, National AcademyPress), provides a summary of the state-of-the-science of landslide hazardresearch, mapping, and assessment in the United States.National Mitigation Strategy—Partnerships for Building Safer Communities(Federal Emergency Management Agency, 1996) provides a framework formitigation of all natural hazards in the United States.The Impacts of Natural Disasters—A Framework for Loss Estimation (Board onNatural Disasters, National Research Council, 1999, National AcademyPress) recommends compilation of a comprehensive data base on losses fromnatural disasters.U.S. Geological Survey Circular 1182, Land Subsidence in the United States(Galloway, Jones, and Ingebritsen, eds., 1999), explores the role of underground water in human-induced land subsidence through case histories.Disasters by Design—A Reassessment of Natural Hazards in the United States(Mileti, 1999, Joseph Henry Press) provides an overview of what is knownabout managing natural hazard disasters, recovery, and mitigation.35Appendix 2. Meetings with StakeholdersIn 1999 and 2000, meetings among various stakeholder organizations were held to obtain input into anational strategy to mitigate landslide hazards. Attendees included State geologists, private consultantsand university professors concerned with landslide hazards, and Federal, State and local government officials whose responsibilities include landslide hazard loss reduction. Many of their recommendations havebeen incorporated into the strategy either through input at meetings or subsequent reviews of this report.The meetings and participants are listed below.Landslide Hazards Mitigation Stakeholders MeetingState Geologists meetingPhiladelphia, PennsylvaniaJanuary 16–17, 1999AttendeeLee AllisonJohn BeaulieuTitleState GeologistState GeologistTom BergVicki CowartJim DavisState GeologistState GeologistState GeologistCharles GardnerState GeologistDon HoskinsState GeologistJohn KieferWilliam ShiltsRandy UpdikeLynn HighlandJohn FilsonAssistant State GeologistState GeologistOrganizationKansas Geological SurveyOregon Department of Geologyand Mineral IndustriesOhio Geological SurveyColorado Geological SurveyCalifornia Department ofMines and GeologyNorth Carolina GeologicalSurveyPennsylvania GeologicalSurveyKentucky Geological SurveyIllinois Geological SurveyU.S. Geological SurveyU.S. Geological SurveyU.S. Geological SurveyLandslide Hazards Mitigation Stakeholders MeetingPrivate sector meetingAlbuquerque, New MexicoFebruary 23–24, 1999AttendeeDon BanksBill CottonBruce ClarkLloyd CluffRichard GrayJim Hamel36Title/CompanyConsultantCotton, Shires & Associates, Inc.Leighton & Associates, Inc.Pacific Gas & ElectricGAI Consultants, Inc.Hamel Geotechnical ConsultantsLocationVicksburg, MississippiLos Gatos, CaliforniaIrvine, CaliforniaSan Francisco, CaliforniaMonroeville, PennsylvaniaMonroeville, PennsylvaniaG.P. JayaprakashJeff KeatonGeorge KierschGeorge MaderRalph PeckBill RoberdsRoy ShelmonRex BaumRandy UpdikeNRC Transportation Research BoardAGRA Earth and Environmental, Inc.Kiersch AssociatesSpangle AssociatesConsultantGolder AssociatesConsultantU.S. Geological SurveyU.S. Geological SurveyWashington, D.C.Phoenix, ArizonaTucson, ArizonaPortola Valley, CaliforniaAlbuquerque, New MexicoRedmond, WashingtonNewport Beach, CaliforniaGolden, ColoradoGolden, ColoradoLandslide Hazards Mitigation Stakeholders MeetingAcademic sector meetingAlbuquerque, New MexicoFebruary 26–27, 1999AttendeeEd CordingHerbert EinsteinArvid JohnsonHoward KunreutherDavid MontgomeryRob OlshanskyNick SitarKeith TurnerErik VanMarckeBob Watters MacKayBob FlemingRandy UpdikeUniversity/OrganizationUniversity of IllinoisMassachusetts Institute of TechnologyPurdue UniversityWharton School, University of PennsylvaniaUniversity of WashingtonUniversity of IllinoisUniversity of CaliforniaColorado School of MinesPrinceton UniversitySchool of Mines, University of NevadaU.S. Geological Survey, Golden, ColoradoU.S. Geological Survey, Golden, ColoradoLandslide Hazards Mitigation Strategy Summit MeetingSan Antonio, TexasAugust 31–September 1, 1999AttendeeDavid ApplegateRex BaumSteven R. BohlenBruce ClarkTimothy CohDerek CornforthVicki CowartKim DavisAnthony de SouzaRobert FakundinyJohn FilsonJohn GrantRobert HamiltonOrganizationAmerican Geological InstituteU.S. Geological Survey, Golden, ColoradoU.S. Geological Survey, Reston, VirginiaLeighton & AssociatesU.S. Geological Survey, Reston, VirginiaLandslide Technology, Portland, OregonColorado Geological SurveyCalifornia Department of ConservationNational Research CouncilNew York Geological SurveyU.S. Geological Survey, Reston, VirginiaNational Aeronautics and Space AdministrationNational Research Council37Lynn HighlandG.P. JayaprakashArvid JohnsonJeff KeatonPat LeahyLindsay McClellandDoug MortonRobert OlshanskyJohn PallisterWilliam RoberdsWilliam ShiltsElliott SpikerRandy UpdikeErik Van MarckeTom YorkeU.S. Geological Survey, Golden, ColoradoNRC Transportation Research BoardPurdue UniversityAGRA Earth & Environmental, Inc., Phoenix, ArizonaU.S. Geological Survey, Reston, VirginiaNational Park ServiceU.S. Geological Survey, Riverside, CaliforniaUniversity of Illinois, Urbana/ChampaignU.S. Geological Survey, Reston, VirginiaGolder Associates, Redmond, WashingtonIllinois State Geological SurveyU.S. Geological Survey, Reston, VirginiaU.S. Geological Survey, Golden, ColoradoPrinceton UniversityU.S. Geological Survey, Reston, VirginiaLandslide Hazards Mitigation Stakeholders MeetingLand-use planners meetingChicago, IllinoisFebruary 17–18, 2000AttendeeSteven BriggsPaula GoriJames A. HecimovichLynn HighlandSanjay JeerGeorge MaderRobert B. OlshanskyJane Preuss, AICPDaniel SentzElliott Spiker38OrganizationCincinnati Planning DepartmentU.S. Geological Survey, Reston, VirginiaAmerican Planning AssociationU.S. Geological Survey, Golden, ColoradoAmerican Planning AssociationSpangle Associates, Portola Valley, CaliforniaUniversity of Illinois – Urbana-ChampaignGeoEngineers, Seattle, WashingtonPittsburgh Department of City PlanningU.S. Geological Survey, Reston, VirginiaAppendix 3. Landslide Hazards and Other Ground Failures—Causes and TypesCauses of LandslidesLandslide is a general term for a wide variety ofdownslope movements of earth materials that resultin the perceptible downward and outward movementof soil, rock, and vegetation under the influence ofgravity. The materials may move by falling, toppling,sliding, spreading, or flowing. Some landslides arerapid, occurring in seconds, whereas others may takehours, weeks, or even longer to develop.Although landslides usually occur on steepslopes, they also can occur in areas of low relief.Landslides can occur as ground failure of river bluffs,cut and-fill failures that may accompany highwayand building excavations, collapse of mine-wastepiles, and slope failures associated with quarries andopen-pit mines. Underwater landslides usuallyinvolve areas of low relief and small slope gradientsin lakes and reservoirs or in offshore marine settings.Landslides can be triggered by both naturalchanges in the environment and human activities.Inherent weaknesses in the rock or soil often combine with one or more triggering events, such asheavy rain, snowmelt, changes in ground water level,falls Abrupt movements of materials that becomedetached from steep slopes or cliffs, moving byfree-fall, bouncing, and rolling.flows General term including many types of massmovement, such as creep, debris flow, debrisavalanche, lahar, and mudflow.creep Slow, steady downslope movementof soil or rock, often indicated by curvedtree trunks, bent fences or retaining walls,tilted poles or fences.debris flow Rapid mass movement inwhich loose soils, rocks, and organic mattercombine with entrained air and water toform a slurry that then flows downslope,usually associated with steep gullies.or seismic or volcanic activity. Long-term climatechange may result in an increase in precipitation andground saturation and a rise in ground-water level,reducing the shear strength and increasing the weightof the soil. Erosion can remove the toe and lateralslope support of potential landslides. Storms and sealevel rise often exacerbate coastal erosion and landslides. Earthquakes and volcanoes often trigger landslides.Human activities triggering landslides are usuallyassociated with construction and changes in slope andsurface-water and ground-water levels. Changes inirrigation, runoff, and drainage can increase erosionand change ground-water levels and ground saturation.Types of LandslidesThe common types of landslides are describedbelow. These definitions are based mainly on thework of Varnes (Varnes, D.J., 1978, Slope movementtypes and processes, in Schuster and Krizek, eds.,Special Report 176, Landslides—Analysis and control: Transportation Research Board, NationalResearch Council, Washington, D.C., p. 12–13).flows—Continueddebris avalanche A variety of very rapidto extremely rapid debris flow.lahar Mudflow or debris flow that originates on the slope of a volcano, usually triggered by heavy rainfall eroding volcanicdeposits, sudden melting of snow and icedue to heat from volcanic vents, or thebreakout of water from glaciers, crater lakes,or lakes dammed by volcanic eruptions.mudflow Rapidly flowing mass of wetmaterial that contains at least 50 percentsand-, silt-, and clay-sized particles.39lateral spreads Often occur on very gentle slopesand result in nearly horizontal movement of earthmaterials. Lateral spreads usually are caused byliquefaction, where saturated sediments (usuallysands and silts) are transformed from a solid into aliquefied state, usually triggered by an earthquake.slides Many types of mass movement are included in the general term "landslide.” The two majortypes of landslides are rotational slides and translational landslides.rotational landslide The surface of ruptureis curved concavely upward (spoonshaped), and the slide movement is more orless rotational. A slump is an example of asmall rotational landslide.translational landslide The mass of soiland rock moves out or down and outwardwith little rotational movement or backwardtilting. Translational landslide material mayrange from loose, unconsolidated soils toextensive slabs of rock and may progressover great distances under certain conditions.40submarine and subaqueous landslides Includerotational and translational landslide, debris flowsand mudflows, and sand and silt liquefaction flowsthat occur principally or totally underwater in lakesand reservoirs or in coastal and offshore marineareas. The failure of underwater slopes can resultfrom rapid sedimentation, methane gas in sediments, storm waves, current scour, or earthquakestresses. Subaqueous landslides pose problems foroffshore and river engineering, jetties, piers, levees,offshore platforms and facilities, and pipelines andtelecommunications cables.topple A block of rock that tilts or rotates forwardand falls, bounces, or rolls down the slope.Appendix 4. Landslide Hazards Mitigation StrategiesOver the past few decades, an array of techniques and practices has evolved to reduce andcope with losses from landslide hazards. Carefulland development can reduce losses by avoidingthe hazards or by reducing the damage potential.Landslide risk can be reduced by the following fiveapproaches used individually or in combination toreduce or eliminate losses.Restricting development in landslide-proneareas.—Land-use planning is one of the mosteffective and economical ways to reduce landslidelosses by avoiding the hazard and minimizing therisk. This minimization is accomplished byremoving or converting existing development ordiscouraging or regulating new development inunstable areas. In the United States, restrictions onland use generally are imposed and enforced bylocal governments by land-use zoning districts andregulations. Implementation of avoidance procedures has met with mixed success. In California,extensive restriction of development in landslideprone areas has been effective in reducing landslide losses. For example, in San Mateo County,California, since 1975 the density of developmenthas been limited in landslide-susceptible areas.However, in many other States, there are no widely accepted procedures or regulations for avoidingor minimizing landslides.Standardizing codes for excavation, construction, and grading.—Excavation, construction, andgrading codes have been developed for construction in landslide-prone areas; however, there is nonationwide standardization. Instead, State and localgovernment agencies apply design and construction criteria that fit their specific needs. The city ofLos Angeles has been effective in using excavationand grading codes as deterrents to landslide activity and damage on hillside area. The FederalGovernment has developed codes for use onFederal projects. Federal standards for excavationand grading often are used by other organizationsin both the public and private sectors.Protecting existing development.—Control ofsurface-water and ground water drainage is themost widely used and generally the most successfulslope-stabilization method. Stability of a slope canbe increased by removing all or part of a landslidemass or by adding earth buttresses placed at thetoes of potential slope failures. Restraining walls,piles, caissons, or rock anchors are commonly usedto prevent or control slope movement. In mostcases, combinations of these measures are used.Utilizing monitoring and warning systems.—Monitoring and warning systems are utilized toprotect lives and property, not to prevent landslides.However, these systems often provide warning ofslope movement in time to allow the constructionof physical measures that will reduce the immediate or long-term hazard. Site-specific monitoringtechniques include field observation and the use ofvarious ground motion instruments, trip wires,radar, laser beams, and vibration meters. Data fromthese devices can be telemetered for real-timewarning.Development of regional real-time landslidewarning systems is one of the more significantareas of landslide research. One such system wassuccessfully developed for the San Francisco Bayregion, California, by the USGS in cooperationwith National Oceanic and AtmosphericAdministration and the National Weather Service.The system is based on relations between rainfallintensity and duration and thresholds for landslideinitiation, geologic determination of areas susceptible to landslides, real-time monitoring of a regionalnetwork of rain gages, and National WeatherService precipitation forecasts.41Providing landslide insurance and compensation for losses.—Landslide insurance is a logicalmeans to provide compensation and incentive toavoid or mitigate the hazard. Landslide insurancecoverage could be made a requirement for mortgage loans. Controls on building, development, andproperty maintenance would need to accompanythe mandatory insurance. Insurance and appropriate government intervention can work together,each complementing the other in reducing lossesand compensating victims. However, landslideinsurance is essentially absent across the Nation,except for mine subsidence coverage in eight Statesand some coverage for landslides due to earthquakes, if earthquake insurance is purchased, andminimal coverage for mudslides by the NationalFlood Insurance Program (Federal EmergencyManagement Agency).The primary reason that insurance companiesdo not offer landslide insurance is the potential foradverse selection by the insured population. Inaddition, if available, it is likely that only thoseindividuals in the most hazardous areas would buy42private landslide insurance. This limited customerbase would lead to very high premiums, perhapsnearly equal to the value of the property. An alternative to private sector insurance is a public insurance program, possibly modeled after the NationalFlood Insurance Program. Incentives to mitigatelandslide hazards must also accompany insurancecoverage, much like fire preventive incentivesappear on current homeowners insurance polices.A major obstacle to implementing some formof landslide insurance is the lack of technical information, maps, and assessments of landslide hazards. A joint study in 1985 by the USGS and theFederal Emergency Management Agency examinedthe feasibility of a nationwide program for identification and delineation of hazards from mudflowsand other landslides. That study concluded thatlandslide hazards can be evaluated and mappednationwide through a systematic sequence of studies, ranging from regional to local in progressivelymore detail. The comprehensiveness and accuracywith which landslide hazards would be delineatedcould be balanced against the costs of the program.Appendix 5. Landslide Hazards Maps and Risk AssessmentsPublic and private organizations need soundeconomic and scientific bases for making decisionsabout reducing landslide-related losses. Quantitative risk assessment is a widely used tool formaking such decisions because it provides estimates of the probable costs of losses and variousoptions for reducing the losses. Such assessments can be either site specific or regional.A risk assessment is based on the probability ofthe hazard and on an analysis of all possible consequences (property damage, casualties, and loss ofservice). Typically, private consultants with expertise in risk assessment, in cooperation with otherpartners or landowners, conduct risk assessmentsbased on the results of the landslide susceptibilityand probability studies. In many cases, private userssuch as insurance companies perform their own riskassessments from the probability data.Regional landslide risk assessments can beaccomplished through public and private partnerships involving the USGS, State GeologicalSurveys, local governments, and private consultants. In such a partnership (1) the USGS and theState Geological Surveys would cooperate to collect the basic geologic map data and landslideinventory data, (2) local governments would provide access to their detailed topographic data basesand records of landslide occurrence, and (3) theUSGS would analyze the geologic, topographic,landslide, and other data to determine landslidesusceptibility and probability.Federal, State, and local government agencies,banks, and private landowners can use probabilityestimates and risk assessments to help identifyareas where expected landslide losses are costlyenough to justify remedial efforts or avoidance.More detailed studies can then be conducted inthese areas to determine the optimal strategy forreducing landslide-related losses.There are four types of landslide hazardsmaps—••••A landslide inventory map (fig. 5–1A)shows the locations and outlines of landslides. A landslide inventory is a data setthat may represent a single event or multiple events. Small-scale maps may showonly landslide locations, whereas largescale maps may distinguish landslidesources from deposits and classify differentkinds of landslides and show other pertinentdata.A landslide susceptibility map (fig. 5–1B)ranks slope stability of an area into categories that range from stable to unstable.Susceptibility maps show where landslidesmay form. Many susceptibility maps use acolor scheme that relates warm colors (red,orange, and yellow) to unstable and marginally unstable areas and cool colors (blueand green) to more stable areas.A landslide hazard map (fig. 5–1C, D) indicates the annual probability (likelihood) oflandslides occurring throughout an area. Anideal landslide hazard map shows not onlythe chances that a landslide may form at aparticular place but also the chances that alandslide from farther upslope may strikethat place.A landslide risk map (fig. 5–1E) shows theexpected annual cost of landslide damagethroughout an area. Risk maps combine theprobability information from a landslidehazard map with an analysis of all possibleconsequences (property damage, casualties,and loss of service).43A, Inventory of landslides triggered bystorms during the winter of 1996-97 overlain on a shaded-relief topographic basemap (U.S. Geological Survey and Shannonand Wilson, Inc.).B, Landslide susceptibility (U.S. Geological C, Probability of landslide occurrenceSurvey).given the event depicted in map A (U.S.Geological Survey and Shannon and Wilson, Inc.).Figure 5–1. Maps showing some of the steps of a regional landslide risk assessment for part of Seattle, Washington. Names inparentheses indicate major contributors of data or analysis. From Baum, R.L., Harp, E.L., Michael, J.A., and Roberds, W.A., 2001,Regional landslide hazard assessment, an example from Seattle, Washington, in Zoghi, M., ed., Contemporary solutions to land massstabilization: Proceedings of the 9th annual Great Lakes Geotechnical and Geoenvironmental Conference.44D, Landslide hazard map, which combinesthe results of map C with an assessmentof landslide travel distance to show theprobability of landslide damage (U.S.Geological Survey and Golder Associates).E, Risk of loss due to landslides (U.S.Geological Survey and Golder Associates).Estimated cost of landslide-related lossesin U.S. dollars.Figure 5–1.—Continued45Appendix 6. Current Landslide Research, Mitigation Activities, andResponsibilities in the United StatesMany Federal, State, and local agencies; academia; and private companies are involved in landslideresearch and mitigation in the United States; however, there is little coordination of landslide hazard mitigation activities. The need for information and cooperation spans the interests of many public and privateorganizations. The National Landslide HazardsMitigation Strategy offers new opportunities formutually advantageous partnerships related to hazardassessments, monitoring, and emergency responseand recovery. Under the strategy, each level of government (Federal, State, and local), nongovernmentalorganizations, businesses, and individuals have someresponsibility for mitigating, responding to, andrecovering from landslide hazards.Federal AgenciesThe Federal role in hazard reduction has itsorigin in the Organic Act of 1879, which createdthe USGS. More recent legislation addressing theFederal role in landslide hazards includes the DamInspection Act of 1972, which stipulated responsibilities for landslide hazards affecting the safety ofdams and reservoirs, and the 1974 Disaster ReliefAct and subsequent reauthorizations, which gavethe USGS responsibility to issue timely disasterwarning of potential landslides.The USGS Landslide Hazard Program is theonly Congressionally authorized program dedicatedto landslide hazards. The USGS National LandslideInformation Center is a prototype clearinghouse forissuing advisories, press statements, and other information about landslides. The USGS has developedexpertise in research, assessment, and mapping oflandslide hazards and provides technical assistanceduring disaster response.The National Science Foundation and theNational Aeronautics and Space Administrationfund landslide hazard research in the academic46community. Personnel of the National Oceanic andAtmospheric Administration—National WeatherService (NWS) provide weather forecasts andassist in emergency response activities. OtherFederal agencies, including the U.S. Army Corpsof Engineers, Bureau of Land Management, ForestService, National Park Service, Office of SurfaceMining Reclamation and Enforcement, andDepartment of Transportation (especially theFederal Highway Administration) have landslidehazard experts and activities relating to lands andinfrastructure under their jurisdiction.The Federal Emergency Management Agency(FEMA) is responsible for emergency managementand long-term mitigation of natural hazards including landslides. FEMA is the Federal coordinatingagency for emergency response, disaster relieffunding, and hazard mitigation efforts. The FederalInsurance and Mitigation Administration, a part ofFEMA, provides insurance coverage for flooddamages, including "mudslides." However, implementation has been difficult because of the absenceof an accepted technical definition of a mudslideand an accepted methodology for delineating mudslide-hazard areas. Landslides other than mudslidesare not insured under this program.State and Local Government AgenciesWhile the Federal Government plays a leadrole in funding and conducting landslide research,in developing landslide mapping and monitoringtechniques, and in landslide hazard managementon Federal lands, the reduction of landslide losseson other lands is primarily a State and localresponsibility. A number of State agencies, commissions, and councils have responsibility for landslide hazards, including those with oversight ofnatural resources, transportation, geology, hazards,emergency services, and land-use issues.States vary in their approaches to landslidehazards. Some States produce inventories of landslides and maps of landslide-prone areas for use bylocal government, business, and the public.However, landslide mapping has been done withoutwidely accepted standards of accuracy, scale, andformat. Some States monitor landslide-prone areasand provide expertise for response and recoveryactivities. Several States conduct research on landslide problems in their State, and a few States haveregulatory authority.The reduction of landslide losses through landuse planning and application of building and grading codes is the function of local government.Localities throughout the Nation differ in their regulatory authority and approach to reducing lossesfrom landslide hazards. Local governments havethe responsibility of issuing warnings of imminentlandslides and managing emergency operationsafter a landslide. FEMA may become involvedafter a Presidentially declared disaster.Landslide hazards have traditionally occupied arelatively modest place in public policy, embodiedin zoning, legal liability, insurance, building codes,land use practices, and environmental quality.Maps showing historic landslides and areas susceptible to landslides have been used only sporadicallyfor zoning and for purposes of real-estate disclosure. Building codes have been drafted for somelocalities to set minimum standards for construction on unstable slopes. Federal and State forestrypractices in many localities include attention tolandslide hazards. Building setbacks from coastalor riverine bluffs have been established in someareas on the basis of projected failure by landsliding. However, broad systematic policy approachesto landslide and other ground-failure hazards arerare, and most areas of the Nation lack the mostfundamental technical information or policies tocope with their hazards.Private and Academic SectorsPrivate sector geologists, engineers, and building professionals are often involved in the identification and implementation of landslide reductionmeasures in building design and planning.University researchers study landslide processesand the development of monitoring and mitigationtechnologies and methods. These professionalsprovide advice to business and industry for loan,insurance, and investment decisions. Professionalsocieties such as the American Society of CivilEngineers, the Association of EngineeringGeologists, and the American Planning Associationserve as conduits of information from researchersto practitioners and practitioners to researchers.Professional societies are generally the source ofmodel codes, handbooks, and professional trainingfor their membership, who in turn use the information to improve the state-of-knowledge of landslideloss reduction in the private and public sectors.47Appendix 7. Federal Agency Landslide Hazard ActivitiesThe Federal role in landslide-hazard reduction involves numerous Federal agencies. The followingFederal agencies provided descriptions of their landslide-hazard reduction activities. Contacts for variousFederal agencies involved in landslide-hazard reduction are listed at the end of this appendix.Department of Agriculture—Forest ServiceThe U.S. Department of Agriculture ForestService is a land-management agency with responsibility for natural resources on national forests.Most of the national forest lands are located in themountainous areas of the Western United States,including large parts of Alaska. The road system innational forests is comparable in size to many Stateroad systems. Consequently, designing low volumeroads to avoid landslide problems and repairing thedamage to them from landslides are major tasks.Additionally, interstate and major State highways,railroad lines, oil and gas pipelines, and electrictransmission corridors pass through the nationalforests. Assessing landslide hazards along such projects is increasingly important.National forests generally occupy the headwatersof major rivers, increasing the importance of watershed management, especially for those watershedswhere anadromous fisheries and significant inlandfisheries are present. Increased landslide activity canproduce sediment loads that degrade water quality andadversely affect fisheries habitat. Landslide hazard canbe a more localized, but equally important, problemon national forests where development of large skiresorts, mines, or hydroelectric facilities takes place.Major wildfires can denude watersheds and lead toshort-term landslide activity. The potential for loss oflife and damage from debris flows initiated by precipitation events on burned watersheds must be consideredin national forests, especially those having developed,private in-holdings and adjacent urban areas.A primary landslide hazard activity conductedby Forest Service personnel is evaluating landslidehazard potential in environmental assessments or inreviewing environmental assessments prepared by48forestry project proponents. Environmental or engineering geologists, as one of their primary duties,minerals geologists, as a related duty, or other earthscientists, where geologists are unavailable, carryout these evaluations. Engineering geologists andgeotechnical engineers carry out environmentalassessments and participate in designs to addresslandslide hazard to system roads.Another activity is assessing damage fromlandslides following major natural disasters. Themost formalized of these assessments is the BurnedArea Emergency Rehabilitation procedure institutedduring major wildfires. This activity also includesparticipating in development of stabilization andrestoration projects to counter wildfire damage.A national geographic information system(GIS) network of national forest lands and a database that includes landslide information is underdevelopment. The landslide hazard information forthis GIS is generated from USGS and StateGeological Survey information and mapping byForest Service geologists. The Research Branch ofthe Forest Service has contributed many studiesthat improve the understanding of landslide hazardsrelative to specific forest management activities.—By Jerome DeGraffForest ServiceDepartment of Commerce—NationalOceanic and Atmospheric AdministrationThe National Oceanic and AtmosphericAdministration (NOAA)—National WeatherService (NWS) is involved in landslide mitigationthrough its role in the Federal Response Plan andits mission of providing services for the protectionof life and property. The National Weather Serviceworks with other Federal, State, and local agenciesby providing forecasts of hydrologic and meteorological conditions for landslide forecasts and mitigation efforts. This assistance may include onscene meteorological personnel to assist in emergency response activities at landslides. The NOAAWeather Radio and other NWS dissemination systems broadcast "Civil Emergency Messages" concerning landslide warnings and response andrecovery efforts at the request of local, State, andFederal emergency management officials.—By Robert LivezeyNational Oceanic and AtmosphericAdministrationDepartment of Defense—U.S. Army Corps of EngineersAs the premier, full-spectrum engineering organization of the United States military, the mission ofthe Corps of Engineers includes planning, design,building, and operating water resources and civilprojects in the areas of flood control, navigation,environmental quality, coastal protection, and disaster response, as well as the design and constructionof facilities for the Army, the Air Force, and otherFederal agencies. In performing this broad mission,the Corps has addressed a full range of technicalchallenges associated with landslides and groundfailure. Corps engineering geologists, geotechnicalengineers, and geophysicists have been involved inthe assessment, monitoring and analysis, and mitigation of landslides in a wide range of settings at locations around the world, as well as basic and appliedresearch on topics directly related to the analysis andmitigation of landslides and ground failures.Landslide assessment activities by Corps scientists and engineers have included investigations oflandslides of various mechanisms and scales alongnavigable waterways such as the Mississippi andOhio Rivers and that result in serious navigation hazards and threats to or loss of flood protection works.Landslides also play an important role in the erosionof the Nation’s shoreline; the protection of shorelineis a major responsibility of the Corps. Many Corpsdam-site investigations have involved the identification and assessment of past and potential landslides.Corps engineering geologists, geotechnical engineers, and geophysicists have been involved in monitoring active landslides and ground failure in both natural and engineered soils and earth materials. Thesetasks have focused on identifying the temporal andspatial variability of earth movements and identifyingcausal factors. Monitoring data have been used alongwith detailed site information to analyze the stabilityof a landslide in terms of initial movements, presentconditions, and conditions after mitigation actions.As an engineering agency, the Corps has a significant role in the planning, design, and construction of landslide mitigation measures associatedwith the protection of its civil and military projects.Specific methods for reducing landslide hazards andincreasing slope stability have been developed andimplemented by Corps engineers at sites around theworld. The Corps’ role in initial engineering geological investigation, engineering analysis, remedialdesign, implementation, construction, and postproject monitoring is of particular value to the Nationand the international community.The Corps has an important national mission indisaster response. This mission has involved theCorps in responding to landslides, especially thoseresulting from floods, hurricanes, volcanic eruptions,and earthquakes. In assistance to FEMA, Corps personnel have provided emergency assessments andimmediate mitigation of past and potential landslides. The Corps’ role in international disasterresponse has become a major focus in landslideengineering. Recent landslide assessments, analysis,and mitigation efforts have been conducted inVenezuela, Honduras, Nicaragua, Colombia, Peru,Haiti, Puerto Rico, South Korea, and the Philippines.Research at the Corps’ Engineering Researchand Development Center includes the developmentand testing of analytical tools and assessment methods and approaches for landslide mitigation. Basicresearch in soil and rock mechanics, geomorphology, hydrogeology, remote sensing, geophysics, andengineering geology has resulted in advancementsin the understanding of the causative factors andmechanics of landslides and ground failures.—By Lawson Smith (deceased)U.S. Army Corps of Engineers49Department of the Interior—Bureau of Land ManagementDepartment of the Interior—National Park ServiceThe Bureau of Land Management is a FederalAgency that manages multiple uses of approximately 264 million surface acres of Federal land locatedprimarily in 12 Western States. A relatively smallportion of this land is located in steep mountainousterrain with geologic and climatic conditions resulting in high landslide hazards, such as in westernOregon, northern California, and northern Idaho.Many landslides on public land are the result ofnatural disturbance events, but land-managementactivities, including road building, timber harvest,historic mining, and water impoundments, can contribute to their occurrence. The Bureau of LandManagement does not have an agencywide landslide hazards program or specialized personnel. Thebureau’s local field office landslide hazards prevention activities include identification of unstableslopes by using aerial photograph interpretation,landslide hazards guides, on-site indicators, predictive models, and limited inventory and monitoringof landslides.Prevention and mitigation of landslides areaccomplished by using a variety of methods.Existing roads may be closed and obliterated,rerouted, or kept open and stabilized with additionalrunoff control structures, subsurface drainage control, or other techniques. Routine road maintenance is an important factor in helping to reducelandslide hazards. Prudent route analysis anddesign to minimize landslide hazard are employedfor new roads in landslide prone areas. Hazardousfuels management can reduce the risk of catastrophic wildfires that could increase landslidehazards. Timber management silvicultural practices are employed to maintain root strength whereneeded for slope stability. Sites that are a threat tohuman health and safety, roads and recreationalfacilities, water quality, fisheries and aquatic habitat, and other resource values are stabilized, andsediment is controlled with revegetation andstructural controls.—By William YpsilantisBureau of Land ManagementMany national parks are geologically active,exposing park visitors, staff, and infrastructure togeologic hazards. Landslides, including slope failures, mudflows, and rockfalls, adversely affectparks, causing deaths and injuries, closing roads andtrails, and damaging park infastructure. Recentexamples include several rockfalls in YosemiteValley, each with one fatality; damaging landslidesin Shenandoah National Park triggered by torrentialrains; repeated slope failures fed by artificialaquifers at Hagerman Fossil Beds NationalMonument; landslides that closed roads in Zion andYellowstone National Parks; and the threat of largedebris flows at Mt. Rainier. USGS scientists haveprovided insights essential to effective response tolandslides hazards at these and other national parks.Because it is a natural process, landslide activity is generally allowed to proceed unimpeded innational parks unless safety is a concern. However,where people have destabilized the landscape (forexample, by logging, mining, and road building),disturbed lands are restored where practical to theirpre disturbance condition.To reduce risk from landslides and other geologic hazards, park planners must incorporate information from hazard assessments and maps into decisions about appropriate sites for facilities such ascampgrounds, visitor centers, and concession areas.Planners face difficult choices as they attempt to balance risks from different hazards, such as floods androckfalls in confined valleys, and at the same timeprovide public access to popular but potentially hazardous areas. When a landslide or other hazardoccurs, park personnel must quickly rescue people,stabilize structures, and clear debris from roads andother public areas. Then park personnel must workwith experts to assess the nature and extent of theevent and the risk of recurrence. Short-term studiesare required to help managers decide whether andwhen to reopen affected areas; then more detailedresearch is often needed to make informed decisionsabout future use of the immediately affected areaand other areas that may face similar hazards.50Park interpretive programs inform visitorsabout key resources and issues, enabling thepublic to better understand geologic hazards.Interpreters communicate directly with visitorsthrough programs such as nature walks and campfire presentations, as well as through exhibits invisitor centers and, in some cases, books andvideos sold by cooperating associations and concessionaires. The National Park Service isincreasingly reaching out to a broader audience,many of whom may not have the opportunity tovisit parks, through innovative methods such asschool programs and Web sites. Interpreters workin partnership with the scientific community toensure that complex information can be conveyedaccurately and in a form that is comprehensibleand relevant to nonspecialists.These and other park programs welcome additional help to assess landslide hazards in parks,provide input to park planning so that infrastructure can be located away from zones of greatestlandslide risk, respond quickly after significantlandslide events, and improve communication withthe public.—By Lindsay McLellandNational Park ServiceDepartment of the Interior—Office of Surface Mining Reclamationand EnforcementThe Office of Surface Mining’s (OSM) role inlandslide mitigation is confined to those landslidesthat are related to past coal mining activity, asauthorized by the Surface Mining Control andReclamation Act. A coal mining technique in theAppalachians involving mountaintop removal andvalley filling is monitored by OSM to prevent serious landslides. Most abandoned mine land landslide areas are reclaimed through State or IndianTribe abandoned mine land programs, funded withOSM grants. The Office of Surface Mining,through its Federal Reclamation Program, hasresponsibility for those States and Tribes that donot have approved programs.When there is an immediate danger to theoccupants of dwellings caused by a landslide,abatement actions are taken immediately throughOSM or State emergency programs. Otherwise,landslide problem areas that endanger humanhealth, safety, and general welfare are assigned priorities, and mitigation actions are taken based onthe highest priority.Reclamation records, maintained in OSM’sAbandoned Mine Land Inventory System, indicatethat OSM and the States and Tribes have completed reclamation on 3,367 acres of dangerous slidesat a cost of $125.25 million. Also, 651 acres aredesignated as high priority and have been funded,but not yet reported as completed, at $30.69 million. An additional 2,276 acres, with an estimatedcost of $73.77 million, are unfunded.—By Gene KruegerOffice of Surface Mining Reclamation andEnforcementDepartment of the Interior—U.S. Geological SurveyThe U.S. Geological Survey (USGS) directlyor indirectly funds and maintains landslide hazardexpertise in several of its programs. The followingprograms direct research and assessment of landslides, debris flows, and lahars caused by storms,earthquakes and volcanoes, submarine landslides,and riverine and coastal erosion.USGS Landslide Hazards Program.—TheUSGS Landslide Hazards Program supports hazard investigations and assessments, research onmonitoring and forecasting landslides, landslideemergency response, operation of the NationalLandslide Information Center in Golden,Colorado, and research and assessment for theimplementation of mitigation strategies forFederal, State, and local land-management andemergency-response agencies. The informationgenerated also provides a basis for land-use planning, emergency planning, and private decisionmaking, including insurance and financial incentives. Much of the current work is being conducted51in the Pacific Northwest, California, and the BlueRidge Mountains in the Eastern United States;most real-time monitoring activities are takingplace in Washington, California, New Mexico,and Colorado.Earthquake Hazards Program.—The USGSNational Earthquake Hazards Reduction Programsupports USGS studies and external, cooperativestudies of landslides caused by earthquakes,including liquefaction investigations in California.It also supports seismic instrumentation of landslide sites.Volcano Hazards Program.—The VolcanoHazards Program funds debris-flow research at theCascades Volcano Observatory. The researchincludes field investigations at Mount St. Helensand Mount Rainier, Washington, and an experimental debris-flow flume in the WillametteNational Forest, Oregon. The Volcano DisasterAssessment Program conducts lahar investigationsinternationally.Coastal and Marine Geology Program.—The Coastal and Marine Geology Program focuseson coastal and submarine landslide studies. Theareas of investigations include California,Washington, Alaska, Hawaii, and Lake Michigan.The program also conducts subsidence studies inLouisiana.National Geologic Cooperative MappingProgram.—The National Geologic CooperativeMapping Program supports comprehensive geologicmapping as a basis for landslide hazard assessmentthrough the matching-fund STATEMAP grantsprogram.Earth Surface Dynamics Program.—The EarthSurface Dynamics Program supports research onlandslide processes and climate history in the BlueRidge in the Eastern United States.Water Resource Programs.—Water Resourceprograms conduct research on landslides, debrisflows, subsidence, and riverine and coastal erosion.Research is also supported through USGS DistrictOffices in Hawaii, Puerto Rico, and other States aslandslides occur.—By Paula L. GoriU.S. Geological Survey52Department of Transportation—Federal Highway AdministrationThe Federal Highway Administration (FHWA)is a part of the Department of Transportation, withfield offices across the United States. The FHWAperforms its mission primarily through the followingtwo programs:••The Federal-Aid Highway Program providesFederal financial assistance to the StateDepartments of Transportation to constructand improve the National Highway System,urban and rural roads, and bridges. The program provides funds for general improvementsand development of safe highways and roads.The Federal Lands Highway Program provides access to and within national forests,national parks, Indian reservations, and otherpublic lands by preparing plans, letting contracts, supervising construction facilities, andconducting bridge inspections and surveys.In support these program areas, the FHWA conductsand manages a comprehensive research, development,and technology program.The FHWA has recognized a need for consistentunderstanding and application of soil and rock slopestability analysis and mitigation for highway projectsacross the United States. These analyses generally arecarried out throughout the life of most highway projects; that is, during planning, design, construction,improvement, rehabilitation, and maintenance. Planners, engineers, geologists, contractors, technicians, andmaintenance workers are involved in the process.To this end, the FHWA geotechnical engineeringprogram continues to develop and support the development of training courses, design manuals, demonstration projects, and geotechnical software. TheFHWA geotechnical engineering program maintainsan ongoing dialogue and exchange of informationwith and among State Departments of Transportationthrough annual Regional Geotechnical Meetings,training courses, and technical assistance providedthrough the FHWA Resource Centers.—By Barry D. SielFederal Highway AdministrationDepartment of Transportation—Federal Railroad Administration•The Federal Railroad Administration's (FRA)primary mission is to promote and regulate railroadsafety. To support its mission, the FRA sponsorsresearch projects to develop and demonstrate techniques for advancing railroad safety and for improving railroad operating and maintenance practices.As with any surface transportation, landslidescan threaten the safety of railroad operations, butlandslide mitigation planning and implementationfor railroads must consider the following characteristics of railroad operations and of the U.S.railroad network. First, warnings must allow fortrains to safely stop in advance of a hazard. Forheavy freight trains or faster passenger trains ondescending grades, stopping distances are often 1to 2 miles. Second, trains cannot steer aroundeven the smallest slides or obstructions. Andthird, especially in the Western United States,there are relatively few alternative railroad routes,and the detour distances for accessing these maybe hundreds of miles long.Landslide mitigation methods on railroads aresimilar to those used for highway transport, mainlyslide fences, rock or slide sheds (in areas of frequent,heavy slides), and anchoring or stabilization ofunstable rock or soil slopes. Slide fences are oftentied into the signal systems, so that any slide ofsufficient intensity to break wires in the fence willcause the signals protecting the nearby section oftrack to show a stop indication; the train dispatchermay also receive an indication. Because of the mitigation efforts that the railroad industry has taken,serious accidents, injuries, and fatalities due to slidesare relatively few, but there are still a considerablenumber of disruptions and delays due to slideevents.Recent FRA landslide mitigation activitiesinclude sponsoring the demonstration of two techniques in the Northwest Corridor (between Vancouver, British Columbia, and Eugene, Oregon) –In addition, the FRA, along with the Associationof American Railroads (AAR) and the NationalCenter for Atmospheric Research (NCAR), sponsored a symposium in 2001 on Enhanced WeatherInformation for Railroad Productivity and Safety. Amajor focus of this symposium was weather andweather events as causes or triggers of natural hazards, including landslides. The FRA also participated in the May 2002 Canadian workshop on NaturalHazard Mitigation on Railroads. This workshopfocused on addressing research needs for hazard riskmanagement, hazard characterization (prediction offrequency and magnitude), and monitoring anddetection technology.Railroad landslide mitigation needs and ideasresulting from the 2001 FRA/AAR/NCAR symposium and the 2002 Natural Hazard workshop wereconsistent with the objectives of the NationalLandslide Hazards Mitigation Strategy, particularlywith respect to the need for improved understanding of slide triggers, better monitoring and detection technology, and the potential benefits of sharing information among different transportation andcommunications organizations with facilities andoperations close to active slide areas. The FRA willcontinue to support work in these areas in partnership with the railroad and research communities.—By Donald PlotkinFederal Railroad Administration•A cellular confinement method for stabilizing slopes subject to failure by weatheringand erosion of the surface layer andA method to install liquid level sensorsfor indicating slope movementFederal Emergency Management AgencyThe Federal Emergency Management Agency(FEMA) has many roles in landslide hazard lossreduction. FEMA has responsibilities in emergencyresponse, disaster recovery assistance, and promotionof landslide hazard mitigation. FEMA coordinatesthe Federal Government’s response to disasters suchas earthquakes, hurricanes, and volcanic eruptionsthat include landslides through the Federal ResponsePlan. The agency provides financial assistance toState and local governments for repair of publicfacilities damaged during these disasters, includingreplacement of lost fill and construction of fill53retaining devices such as gabions and rock toes. Following disasters, the agency also supports installationof mitigation measures, such as installing drainageditches to direct flow away from the landslide areas.FEMA provides relief to individuals who havesustained losses due to mudslides and who areinsured under the National Flood Insurance program.However, the distinctions that the agency makesbetween landslides and mudslides have been a sourceof controversy, as the agency provides only limiteddamage coverage. Also encouraging mitigation measures in tandem with insurance coverage, which is acornerstone of the flood insurance program, has beenimpossible because, to date, there are no maps thatdelineate mudslide zones and no standards governingdevelopment in mudslide-prone areas.FEMA promotes landslide-hazard mitigation bydeveloping State and national guidebooks for landslide loss reduction, including a prototype mitigation plan that can be incorporated into existing hazard mitigation plans. Through its Disaster-ResistantCommunities project, FEMA is encouraging localjurisdictions to implement mitigation programs thatreduce, among other hazards, landslides.—By Ed PasterickFederal Insurance AdministrationNational Science FoundationAccording to the National Science FoundationAct of 1950, the mission of the National ScienceFoundation (NSF) is to promote the progress ofscience; to advance the national health, prosperity,and welfare; and to secure the national defense.The NSF provides funding for landslide and slopestability research through several programs—••The Geotechnical and GeoHazards Systems(GHS) Program (http://www.eng.nsf.gov/cms/ghs.htm), under the Division of Civiland Mechanical Systems in the Directoratefor Engineering (CMS/ENG)The Hydrologic Sciences Program and theGeology and Paleontology Program, underthe Division of Earth Sciences in the Directorate for Geosciences (EAR/GEO)In the Directorate for Engineering, fundingmechanisms include peer reviewed unsolicited proposals, support for workshops, Small Grants forExploratory Research, and the CAREER Program(http://www.nsf.gov/pubsys/ods/getpub.cfm?gp). TheGHS Program does not have solicitations directedspecifically toward landslide and slope stabilityresearch; all current research in this area is the resultof unsolicited proposals. Historically, GHS has supported development of numerical analysis techniques for slope stability, landslide mitigation techniques, investigations of seismic slope stability andearthquake induced submarine landslides, constitutive and rheological model development related toslope stability and mud and debris flows, and postlandslide reconnaissance. Current GHS-fundedresearch includes development of probabilistic methods of stability analysis, analysis of the role of strainlocalization and dilatancy on slope stability, development of Time Domain Reflectometry sensors forearly warning of slope movement, using geographicinformation systems to evaluate the factors controlling seismic slope stability, and stabilization ofslopes by using in-situ reinforcement.In the Directorate for Geosciences, theHydrologic Sciences Program supports work onlandslide triggering caused by high water contents insoils and lubricating slip planes between strata; theGeology and Paleontology Program focuses on therole of landslides in reshaping the Earth's surface.Both programs interact with other NSF earth scienceprograms to study landslide triggering by earthquakes or volcanic events. Projects include studieson diffusive soil transport as a process in hillslopeevolution and studies on reconstructing landslidehistory. The NFS is also starting a Science andTechnology Center at the University of Minnesota;here new analytical tools will be refined and developed to study the various processes that sculpt theEarth's surface. A major focus will be the study ofthe patterns in which landslide materials accumulateover sequential events. The simulation of thisprocess is receiving growing attention as a tool inmapping aquifer properties.—By Richard J. FragaszyNational Science FoundationContactsJerome DeGraffDepartment of AgricultureForest ServiceSierra National Forest1600 Tollhouse RoadClovis, CA 93611E-mail: Fishlake@worldnet.att.netTelephone: 209-297-0706, X4932Fax: 209-222-4122Jerry DiMaggioDepartment of TransportationFederal Highway Administration400 7th Street, SW., HNG-31Washington, DC 20590E-mail: Jerry.Dimaggio@fhwa.dot.govTelephone: 202-366-1569Fax: 202-366-3378Richard J. FragaszyGeomechanics and Geotechnical SystemsCivil & Mechanical Systems DivisionNational Science Foundation4201 Wilson Blvd., Room 545Arlington, VA 22230E-mail: rfragasz@nsf.govTelephone: 703-292-7011Paula L. GoriDepartment of the InteriorU.S. Geological Survey904 National CenterReston, VA 20192E-mail: pgori@usgs.govRobert HigginsDepartment of the InteriorNational Park ServiceGeologic Resources DivisionP.O. Box 25287Denver, CO 80225E-mail: Robert-Higgins@nps.gov>Telephone: 303-969-2018Fax: 303-987-6792Michael J. KlostermanDepartment of DefenseU.S. Army Corps of Engineers441 G Street, NW.Washington, DC 20314E-mail: michael.klosterman@usace.army.milTelephone: 202-761-5887Fax: 202-761-0633Gene KruegerDepartment of the InteriorOffice of Surface Mining Reclamationand Enforcement1951 Constitution Ave., NW.Washington, DC 20240E-mail: GKRUEGER@OSMRE.GOVTelephone: 202-208-2937Robert LivezeyDepartment of CommerceNational Oceanic and Atmospheric AdministrationClimate Prediction CenterN/NP51 NOAA Science CenterCamp Springs, MD 20746E-mail: Robert.E.Livezey@noaa.govTelephone: 301-763-8155Fax: 301-763-8395Lindsay McLellandDepartment of the InteriorNational Park Service908 National CenterReston, VA 20192E-mail: Lindsay-Mclland@NPS.govTelephone: 202-208-4958, X6610Fax: 202-208-4620Ed PasterickFederal Insurance AdministrationFederal Emergency Management Agency500 C Street, SW.Washington, DC 20472E-mail: Edward.pasterick@fema.govTelephone: 202-646-344355Donald PlotkinResearch Program ManagerDepartment of TransportationFederal Railroad AdministrationOffice of Research and Development1120 Vermont Avenue - Mail Stop 20Washington, DC 20590E-mail: Donald.Plotkin@fra.dot.govTelephone: 202-493-6334Fax: 202-493-6333Barry D. SielDepartment of TransportationFederal Highway AdministrationWestern Resource Center555 Zang Street, No. 400Lakewood, CO 80228E-mail: barry.siel@fhwa.dot.govTelephone: 303-716-2294Fax: 303-969-672756William YpsilantisDepartment of the InteriorBureau of Land ManagementP.O. Box 25047Denver Federal Center, Building 50Denver, CO 80225–0047E-mail: bill_ypsilantis@blm.govPublished in the Eastern Region, Reston, Va.Manuscript approved for publication October 28, 2002