U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

EARTHQUAKE HAZARDS PROGRAM

Program Priorities 1999-2004

EXECUTIVE SUMMARY

The Earthquake Hazards Program (EHP) of the U.S. Geological Survey (USGS) is part of the National Earthquake Hazards Reduction Program (NEHRP) led by the Federal Emergency Management Agency (FEMA).

The Vision of the NEHRP is a future in which all seismically vulnerable regions of the United States have practices and policies that minimize earthquake impacts on the public and private sector.

The Mission of the NEHRP is to develop and promote knowledge, practices, and policies that reduce fatalities, injuries, and economic and other losses from earthquakes.

The USGS role in NEHRP is to provide Earth sciences information and products for earthquake loss reduction. The goals of the USGS earthquake program are:

These goals represent the program priorities for the period 1999-2004. These goals are inextricably linked and form a tripod that supports earthquake loss reduction efforts. The effectiveness of each element is dependent on the other two.

These goals are consistent with Goals 1 and 2 of the Science Strategy of the Geologic Division of the USGS, 2000-2010 which are:

PROGRAM SUMMARY

1. Improve earthquake hazard identification and risk assessment methods and their use

The USGS EHP will produce and demonstrate the application of products that enable the public and private sectors to assess earthquake hazards and implement effective mitigation strategies.

An important contribution of the USGS EHP is the series of national probabilistic seismic shaking hazard maps that are produced and updated periodically with new and refined information. These maps have grown out of the research efforts and systematically quantify the seismic shaking hazard for our Nation. They are used as input for many policy decisions on building codes and land use. In support of these maps, the USGS EHP will produce accessible GIS databases of active earthquake source zones with up-to-date information on slip rates and recurrence intervals.

For selected urban areas at high risk from earthquakes, the USGS EHP plans reports estimating the probabilities of strong earthquakes, detailed maps of shaking amplification and susceptibility to liquefaction and landslides, and planning scenarios of large urban earthquakes. These products will be developed in cooperation with State geological surveys and local committees of users and will be used by planners, engineers, and emergency managers to reduce seismic vulnerability. The USGS will cooperate with the (FEMA) to evaluate comparative earthquake loss potential for major urban areas across the Nation and to conduct a state-of-the-art estimate of potential earthquake losses for an urban area where earthquake hazard mapping has been completed.

2. Maintain and improve comprehensive earthquake monitoring in the United States with focus on "real-time" systems in urban areas, and

The USGS will lead the national program in modernizing and expanding collection, interpretation, and dissemination of earthquake information, particularly in urban areas.

Because national and international agencies look to the USGS for quick and reliable earthquake information, it is essential to maintain monitoring capabilities nationally and worldwide. Products and research of the USGS EHP have been largely data driven (e.g., earthquake probabilities and ground shaking estimates are largely empirically derived), so the EHP invests significant resources in instrumental programs. Seismic and crustal deformation monitoring networks can provide real-time information for emergency response, as well as record strong-motion data for engineering applications; however, the entire infrastructure of seismic monitoring in the United States needs modernization. During the next five years the monitoring program will focus on developing real-time information earthquake information systems for urban areas with high to moderate seismic risk. These systems can provide within minutes of an event information on the distribution and severity of strong ground shaking in an urban area, invaluable engineering data on ground and building response during and earthquake, and have the potential for providing a few seconds warning of strong ground shaking from earthquakes a few tens of miles distant.

3. Improve the understanding of earthquakes, earthquake occurrence, and their effects and consequences.

The USGS EHP will pursue earthquake research to understand earthquake occurrence and effects for the purpose of developing and improving hazard assessment methods and loss reduction strategies.

Because the hazard information products of the EHP derive from research efforts, the USGS EHP will continue a major focus on understanding earthquake occurrence in space and time. Critical areas of interest in earthquake occurrence include earthquake triggering, fault interactions, the role of aseismic slip in relieving the buildup of crustal strain. Reducing future earthquake losses depends on an understanding of the damaging effects of earthquakes. Critical areas of interest in earthquake effects include the effects of the earthquake source, local and regional geologic structures, and near-surface geological deposits on strong ground shaking. Other areas in need of research include the factors that govern susceptibility to ground failure from landsliding, liquefaction, and lateral spreading and the seismic behavior of structures during earthquakes.

CHANGES IN PROGRAM DIRECTION IN RESPONSE TO DIVISION SCIENCE STRATEGY, EMERGING LONG TERM ISSUES

Over the next 5 years, the USGS EHP will contribute to the reduction of casualties, property damage, and economic losses from earthquakes by providing a firm scientific basis for improved hazard assessments and loss mitigation strategies and by demonstrating the application of new knowledge and techniques to loss reduction activities. The EHP will pursue the various goals, objectives, and tasks adopted under its current five-year plan, assigned to the USGS under the NEHRP authorization legislation, proposed to Congress through the annual appropriation process, and those set down in the Geologic Division Science Strategy (GDSS).

The EHP is concerned chiefly with Goals 1 and 2 of the GDSS. Fortunately, these goals are consistent with the current direction of the EHP. Specific directions of the EHP in response to the GSDD are discussed below.

GDSS Goal 1. Conduct geologic hazard assessments for mitigation planning.

• National earthquake hazard maps are complete and are currently being adapted for the seismic design elements of the new International Building code. These maps will be reviewed, and revised if necessary, every three years.
  
• Earthquake hazard maps for Hawaii, Alaska, Puerto Rico and the Virgin Islands are under development.
  
• Urban hazard studies for the San Francisco Bay, Seattle, and Memphis regions are underway. These three urban areas will be the focus of EHP hazard assessment work at regional scales for the next few years.
  
• Concerted efforts are underway to determine how geologic basins alter strong ground shaking due to earthquakes. There are many examples (including Mexico City and Armenia) where geologic basins filled with loosely consolidated sediments have amplified ground shaking with disastrous results. Current emphasis in on the Santa Clara Valley in northern California and the San Bernardino area of southern California.

GDSS Goal 2. Provide short-term prediction of geologic disasters and rapidly characterize their effects

• The EHP is emphasizing the development of real-time earthquake notification systems in southern California, and in northern California and elsewhere as funding permits.
  
• The ERP timely information on earthquakes within the U.S. and worldwide through the National Earthquake Information Center and is working to reduce the time delay and improve the accuracy of this information.

PROGRAM PRIORITIES 1999-2004

1. Improve earthquake hazard identification and risk assessment methods and their use

National and Regional.

• Produce, review on a three-year cycle, and revise as necessary a set of updated and improved national probabilistic seismic shaking hazard maps. The USGS will collaborate with the State geological surveys and other organizations in order to accomplish this task.

• Improve the national probabilistic seismic shaking hazard maps through compilation of a national earthquake catalog with consistent magnitudes, development of improved ground-motion attenuation relations for the Central and Eastern U.S., and increasing knowledge of earthquake source zones and recurrence rates in the United States.

• Collaborate with multidisciplinary working groups and organizations (such as the Applied Technology Council, the Building Seismic Safety Council, the Earthquake Engineering Research Institute, the Insurance Institute for Property Loss Reduction, American Planning Institute, regional consortia, etc.) to develop the most effective means to transfer knowledge of the use, advantages, limitations, and future developments of the national probabilistic seismic shaking hazard maps to various professional groups (engineers, the insurance industry, utility operators, land use planners, etc.). Collaborative efforts with these groups and cooperative funding of these efforts will leverage the ability of the USGS to provide these crucial knowledge transfer activities.

• Compile GIS databases of existing data on active earthquake source zones and make these databases easily accessible to user groups.

• Determine and refine prehistoric earthquake chronologies for high-risk seismically active regions. Continue efforts at current levels in California, Cascadia, New Madrid, and the Wabash Valley. Initiate exploratory efforts in the Northeastern U.S. Without collaboration and sharing of costs, no other areas will be studied in the foreseeable future.

High-Risk Urban Areas

• For the San Francisco, Memphis, and Seattle urban areas, develop digital geologic and geotechnical databases and prepare demonstration large-scale seismic hazard maps by 2002. This work will be done in close coordination with State geologists and local committees and, funding permitting, will include:

• compiling digital surficial geology maps;
• preparing ground shaking amplification maps;
• preparing liquefaction and lateral spreading susceptibility maps; and
• preparing landslide susceptibility maps.

• In an urban area with completed large-scale hazard mapping, cooperate with FEMA, emergency management officials, and State geologists to conduct a state-of-the-art loss estimation using HAZUS and incorporating complete digital seismological, geological, and geotechnical data. Cooperative funding will be sought from FEMA and other government and private groups that will use the loss estimates.

• By 1999, produce an updated 30-year probability report for the San Francisco Bay Region.

• By 2000, in cooperation with the State geologist and a local committee, create and publish a state-of-knowledge earthquake probability report for Salt Lake City.

• In coordination with State geologists, State and local emergency management agencies, and local committees, create and publish credible planning earthquake scenarios for selected cities.

Outreach

• Collaborate with working groups, professional organizations, and regional consortia to develop the most effective means to communicate seismic hazard issues and better determine the needs of user groups. These information transfer activities are ideally funded through cost sharing efforts with the various interested organizations. The USGS can provide the expertise and the working groups, professional organizations, and regional consortia can provide the translation to the needs of their constituencies.

• Through workshops and publications, provide the public, the private sector, and government agencies with general information on earthquake hazards as well as information specific to their regions.

2. Maintain and improve comprehensive earthquake monitoring in the United States with focus on "real-time" systems in urban areas
   

Seismic Monitoring

• Integrate the USNSN and EHP-supported regional seismic networks into the National Seismic System (NSS) with the goal of monitoring U.S. earthquakes down to magnitude 3. Regional seismic monitoring will be maintained in cooperation with universities in high seismicity, populated areas of California, the Pacific Northwest, the Central Mississippi Valley region, Nevada, Utah, Alaska, and the Eastern U.S.

• Develop real-time systems in urban areas at high to moderate risk from damaging earthquake for rapidly determining the severity and distribution of strong earthquake shaking. This information is critical to emergency managers in the few minutes after a damaging earthquake and to engineers and architects engaged in the design of earthquake resistant structures for long-term mitigation. Progress will depend on funding for these new systems from cooperating government agencies and the private sector, as has been realized in southern California through the TriNet initiative orchestrated by the USGS, the California Institute of Technology, and the California Division of Mines and Geology. Funding for the dense urban networks will be sought through initiatives and cooperative efforts.

• Through the National Strong Motion Program, maintain instruments in seismically active regions to quantify free-field strong ground shaking. These strong-motion networks will be operated in conjunction with the regional seismic networks. There will be a timely and easily accessible database of all significant strong-motion records for the engineering community.

• Upgrade outdated analog regional networks and strong-motion sites to digital recording with modern telemetry capabilities so essential seismic data can be collected more effectively and efficiently. Funding for the hardware improvements of existing networks will be sought through budget initiatives and through other cooperative efforts.

Crustal Strain Monitoring

• Maintain crustal deformation monitoring in active seismic areas of California, the Pacific Northwest, the Central U.S., Nevada, Utah, and Alaska for understanding the strain fields associated with earthquakes.

• Cooperate with the National Aeronautics and Space Administration (NASA) and the National Science Foundation (NSF) in testing dense continuous GPS monitoring capability in southern California for scientific observation of crustal deformation and real-time monitoring of geologic and manmade structures. Progress depends on cooperative funding for the Southern California Integrated GPS Network (SCIGN), which is being provided by USGS, NASA, NSF, and private donations.

• Investigate Interferometric Synthetic Aperture Radar techniques for providing map images of fault slip and areal crustal deformation associated with earthquakes.

Post-earthquake Investigations

• Work with government agencies and universities to coordinate scientific earthquake responses and post-earthquake investigations. Focus on providing immediate hazard information and investigating the faulting process and the earthquake source, seismic shaking and ground failure effects, and damage patterns.

• Provide, within 2 years of a significant earthquake, a report of the post-earthquake investigations for the public. Prepare an in-depth report of scientific findings within 4 years.

3. Improve the understanding of earthquakes, earthquake occurrence, and their effects and consequences.
   

Physics of Earthquake Occurrence

• In well-defined experiments, test stated hypotheses on the initiation, propagation, and arrest of seismic rupture.

• Continue the focused fault-monitoring experiment at Parkfield, California. An independent review in 1993 concluded that Parkfield remains the best place to "trap" a moderate-sized earthquake and thereby answer important scientific questions about the earthquake source.

• Collect and analyze geologic evidence of prehistoric earthquakes and other data to determine the times between successive earthquakes in different tectonic settings.

• Use geodetic and geologic techniques to determine crustal strain rates, compare these strain rates with long-term seismic moment release, fault slip rates, and modeled plate rates, and investigate how all of these quantities are related to future earthquake potential.

• Develop and test hypotheses to explain the features of aftershocks and foreshocks that have been identified through statistical analysis.

• Continue study of the stress changes produced by significant earthquakes, which may allow the most likely locations of aftershocks to be forecast, as well as further mainshocks within a period of time. Express results as earthquake probability estimates.

Earthquake Effects

• Develop improved methods to calculate synthetic seismograms for future earthquakes, incorporating improved understanding of the rupture process and information about the fault and the properties of the surrounding Earth's crust. These synthetic seismograms must accurately simulate a number of parameters used by structural and geotechnical engineers: peak acceleration, ground velocity and displacement; response spectra; and shaking duration.

• Characterize basin structure for the Santa Clara and San Bernardino areas well enough to test 3-D numerical simulations of basin response. Conduct shallow, high-resolution, active-source seismic surveys to determine compression and shear wave velocities in the upper 5 km.

• Investigate causes for enhanced shaking response by collecting data on subsurface seismic velocities and densities at sites where there are weak and strong-motion recordings of enhanced ground motion.

• Develop techniques to estimate the permanent ground deformation and displacement resulting from earthquake-induced landslides and liquefaction.

• Analyze existing data to examine the response of structures, to identify the parameters of ground motion that control damage to structures (such as acceleration, velocity, shaking duration, and spectral content), and to investigate soil-structure interaction.

• Record data documenting input ground motion as well as structural response in selected structures in seismically active areas. Partnerships with professional associations, Federal and State agencies, and building owners must be sought for instrumentation of structures.

Expertise, facilities needed

Expertise

The EHP needs additional expertise in the following areas:

• Geophysical and geological modeling of the shallow crust using seismic, geodetic, and geological data and information for earthquake hazard evaluation.
  
• Paleoseismology
  
• Engineering for the purpose of making USGS EHP products applicable to the design and construction of earthquake resistant buildings and structures.
  
• Surficial geologic mapping and site characterization for urban hazard assessments.
  
• Theoretical development and application of earthquake probabilities and risk assessments.
  
• Most importantly, the EHP needs competent, well rounded scientists who can work in a field office or out of a regional center with local groups, private and government, to build support for the EHP, develop external partnerships, and expand the "customer base".
  
• Finally, the EHP needs capable scientists interested in meeting the challenges and developing the opportunities presented by program management.
  

From the program perspective, more use should be made of contract personnel for the routine tasks involved in seismic and geodetic network installation and maintenance and routine data analysis.

Facilities Needed

Complete modernization of the various seismic networks supported by the EHP is required. This will cost approximately $170 million.

The recent movement of offices in Menlo Park should reduce space charges there. Considerable effort will be needed by managers to maintain programmatic cohesiveness between EHP personnel.

The office spaces in Golden, Colorado, are adequate and the common spaces in this building may be excessive. The regional management should review the use of this space.

Expansion of the EHP in the eastern U.S. (Reston) is sought.

The EHP maintains small field offices in Pasadena, Memphis, and Seattle. These offices have proved extremely effective in building local support for the EHP and expanding the "customer base". These offices should be expanded and additional offices established in Salt Lake City, Fairbanks or Anchorage, and Reno

Resources — Five Year Funding Profile (in $1,000)

Opportunities and Plan for inter program (inter GD, inter Bureau, inter-agency ) cooperative efforts

Inter program opportunities exist with all Geologic Division programs; but, these opportunities must developed in terms of EHP needs.

Inter Division opportunities are being developed and should increase. WRD personnel are helping the Memphis area hazard study and similar efforts are beginning in southern and northern California. EHP personnel are supporting the development of the CINDI by NMD. Expanded cooperation with NMD scientists and experts in Sioux Falls is needed.

EHP has been cooperating with NASA, NOAA, NSF, the Corps of Engineers, and other federal agencies. This cooperation will continue and be expanded as opportunities arise. The challenge in these cooperative efforts is to have the EHP accepted as a full partner.

Opportunities for reimbursable project development

In the past, most of the opportunities for reimbursable project development have arisen through EHP contacts with other federal agencies. These opportunities continue to exist but new ones are arising with regional and local interest. The CRADA with Pacific Gas and Electric in northern California is an excellent example of this type. The EHP has more international opportunities than it can support. Most of these come with no salary support.