Statement of Charles G. Groat, Director, USGS, May 8, 2003

Statement of Charles G. Groat, Director, USGS before the subcommittee on Research Committee on Science
U.S. House of Representatives

"The National Earthquake Hazards Reduction Program:  Past, Present, and Future"

May 8, 2003

INTRODUCTION

The U.S. Geological Survey (USGS) has been an active participant in the National Earthquake Hazards Reduction Program (NEHRP) for twenty-five years. Within NEHRP, USGS provides the fundamental earth sciences information, analyses, and research that form the foundation for cost-effective earthquake risk reduction measures.

Earthquakes are the most costly, single event natural hazard faced by the United States. Twenty-five years of work by USGS, in close cooperation with the three other NEHRP agencies (Federal Emergency Management Agency (FEMA), National Institute of Standards and Technology (NIST), and National Science Foundation (NSF)), has yielded major advances in earthquake preparedness and monitoring, as well as a vastly improved understanding of earthquake hazards, effects, and processes. Through NEHRP, USGS is poised to build on these accomplishments, helping to protect lives and property in the future earthquakes that will strike the United States. In FY2003, USGS received $46.6 million in appropriated funds to support NEHRP work. The three major activities of USGS within NEHRP and the percentage of funds supporting these activities are given below:

• Assessment and quantification of seismic hazards. The USGS produces and demonstrates the application of products that enable the public and private sectors to assess earthquake risks and implement effective mitigation strategies. (40%)
• Operation, modernization, and expansion of real-time earthquake notification and monitoring systems. The USGS operates the national program in collecting, interpreting, and disseminating information on earthquake occurrences throughout the U.S., and significant earthquakes worldwide, in support of disaster response, scientific research, national security, earthquake preparedness, and public education. (40%)
• Increasing scientific understanding of earthquake processes and effects. The USGS pursues research on earthquake processes and effects for the purpose of developing and improving hazard assessment methods and loss reduction strategies. (20%)

The work of USGS Earthquake Hazards Program is focused on the Nation as a whole and on five broad geographical regions, addressing particular regional needs and problems in areas where the earthquake risk is the greatest. These regions are Southern California, Northern California, the Pacific Northwest (including Alaska), the Intermountain West, and the central and eastern United States (including Puerto Rico).

Approximately one-fourth of the USGS NEHRP funding is used to fund activities, investigations, and research outside USGS. Each year we support approximately 100 research grants at universities, state governments, and in the private sector. The USGS is engaged in some 16 cooperative agreements to support the operations of 14 regional seismic networks maintained by universities. In a cooperative effort with NSF, USGS provides support to the Southern California Earthquake Center, a leading effort in earthquake research at the University of Southern California. By involving the external community, through research grants and cooperative agreements, the USGS program increases its geographical and institutional impact, promotes earthquake awareness across the Nation, encourages the application of new hazards assessment techniques by State and local governments and the private sector, and increases the level of technical knowledge within State and local government agencies.

USGS NEHRP ACTIVITIES

Earthquake Hazard Assessments. The USGS carries out quantitative earthquake hazard assessments on national and regional scales. The national seismic hazard assessments are used to form the seismic safety elements of model building codes for the United States. These maps integrate results of geologic mapping, field studies of fault locations and slip rates, analyses of seismicity patterns and rates, and crustal deformation measurements. The maps are prepared in digital format and give, at some 150,000 grid points nationwide, the severity of expected ground shaking (in terms of horizontal acceleration and velocity) over exposure times of 50, 100, and 250 years. The maps and their associated databases are used also to predict earthquake losses and to define insurance risks. Periodic review and revision of these maps, as new data become available, is a high priority in the USGS NEHRP program. The latest revision of these maps was completed in 2002.

The national scale earthquake hazard maps do not take into account variations in the amplitude and duration of seismic shaking caused by local geologic structures and soil conditions. For example, artificially filled land and shallow geologic basins filled with loosely consolidated sediments tend to amplify and extend earthquake shaking to dangerous levels. The USGS works in areas of high to moderate seismic risk, such as San Francisco, Los Angeles, Seattle, and Memphis, to produce large-scale maps and databases that show the variations in ground shaking patterns that can be expected from local conditions.

In addition to not taking into account variations in local geology, the national scale assessments do not take into account the time dependence of earthquake occurrence. For example, if a large, magnitude 8 earthquake occurs on the northern San Andreas fault in California tomorrow, is unlikely that an earthquake of similar magnitude will occur on the same fault a year from now, simply because a large portion of the tectonic strain in the region will have be relieved. Studies of the regional "strain budget" result in forecasts of the probabilities of future earthquakes on individual active faults and across the region as a whole. The USGS is in the process of publishing an exhaustive study of the earthquake probabilities in the San Francisco Bay region. This study estimates a 62% chance of an earthquake of magnitude 6.7 or greater in the region before 2031.

Earthquake Monitoring and Notification. The USGS is the only agency in the United States responsible for the routine monitoring and notification of earthquake occurrences. The USGS fulfills this role by operating the U.S. National Seismograph Network (USNSN), the National Earthquake Information Center (NEIC), the National Strong Motion Program (NSMP), and by supporting 14 regional networks in areas of moderate to high seismic activity. All of these efforts are being integrated into the Advanced National Seismic System (ANSS). Rapid and reliable information on the location, magnitude, and effects of an earthquake is needed to guide emergency response, save lives, reduce economic losses, and speed recovery. Additionally, the seismic data from routine network operations are essential to define and improve the models of earthquake occurrence, fault activity, and earth structure that underlie earthquake hazards assessments and research on earthquake effect and processes.

The same analysis systems and facilities that process data for domestic earthquakes use data from the Global Seismograph Network (GSN) to monitor foreign earthquakes. Notifications of large foreign earthquakes are provided to the Department of State, the Office of Foreign Disaster Assistance, the Red Cross, and the news media.

The ANSS is an effort to integrate, modernize, and expand earthquake monitoring and notification nationwide. This effort was authorized in the last reauthorization of NEHRP in 2000 (P. L. 106-503). Although appropriations have not reached the authorized level, significant progress has been made in the development of the ANSS. A management structure is in place that includes regional implementation and advisory groups with national level oversight and coordination. By the end of 2003, USGS and its regional partners will have installed some 400 new seismic sensors in urban areas of the United States. These areas include Los Angeles, San Francisco, Seattle, Salt Lake City, Reno, Anchorage, and Memphis. Data from earthquake sensors in urban areas can be used to produce, within a few minutes of an earthquake occurrence, a map showing the actual severity and distribution of strong ground shaking caused by an earthquake. Emergency management officials and managers of transportation, communication, and energy grids use these "ShakeMaps" to direct the response to the earthquake, minimize it effects, and speed recovery. Data from these "Shake Maps" can be imported into FEMA´s HAZUS GIS based loss estimation tool to provide extremely reliable results. Some form of ShakeMap capability now exists in Los Angeles, San Francisco, Seattle, and Salt Lake City.

ANSS sensors in urban areas also provide the data necessary to improve earthquake resistant building design and construction practices. These instruments will provide quantitative data on how the ground actually shook during an earthquake. These data will serve as the input to engineering studies to improve site characterization and infrastructure (bridges, buildings, lifelines, etc.) performance, such as the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) sponsored by NSF.

Better Understanding of Earthquake Processes and Effects. With the goal of improving hazard assessments, earthquake forecasts and earthquake monitoring products, USGS conducts and supports research on earthquake processes and effects. This is a effort to increase our understanding of the tectonic processes that lead to earthquakes, the physics of earthquake initiation and growth, the propagation of strong shaking through the earth´s crustal and surficial layers, and the triggering of landslides, rock falls, and other ground failures by seismic shaking. This research is based on theoretical, laboratory, and field studies and addresses many of the fundamental problems of earthquake occurrence and consequences.

Working with User Communities. The USGS believes that all of its work under NEHRP must relate to reducing public risk from earthquake hazards. We make strong efforts to engage the communities of users of our information, assessment products, and research.

The development of the national seismic hazard maps involves an exhaustive process in which we engage seismologists, geologists, and engineers on the regional and national levels. Regional workshops are held at which new data and studies on earthquake hazards are presented and discussed. The changes that will result in incorporating the new results into revised maps are also presented and discussed. Every effort is made to reach a consensus on the validity of the new results and on the resulting changes in the hazard maps. At the national level, we work with FEMA, the National Institute of Building Safety, the Building Seismic Safety Council, the Building Officials Conference of America, and the American Society of Civil Engineers to ensure that the maps are of maximum practical use to the engineering and construction communities.

Our work on regional hazard assessments in northern and southern California, Seattle, and Memphis is carried out in participation and collaboration with regional and local governments and local interest groups. These groups provide essential input on what information is needed and the form in which it is needed to be of greatest practical use.

Within the ANSS management structure, there are six regional advisory committees and a national steering committee. These committees are made up of engineers, seismologists, and emergency management officials. The regional advisory committees ensure that the implementation of ANSS meets regional requirements; the national committee ensures that the program is developed as an integrated system with national operating standards and equipment specifications.

In 2002, under the authority of P.L. 106-505, USGS established a Scientific Earthquake Studies Advisory Committee to advise USGS on its roles, goals, and objectives within NEHRP, to review its capabilities and research needs, and to provide guidance on achieving major objectives and performance goals. Members of this Committee have backgrounds in geology, seismology, and engineering and represent academia, state governments, and the private sector. The Committee has met three times during the past year and has provided two reports to this Committee on its findings.

The USGS maintains close ties with professional groups such as the Seismological Society of America, the Earthquake Engineering Research Institute, and the American Geological Institute. We also work closely with and support regional groups such as the Central United States Earthquake Consortium, the Western States Seismic Policy Council, the Cascadia Region Earthquake Working Group, and various state geological surveys and seismic safety commissions.

At the Federal level, in additional to working with our NEHRP colleagues, we have strong ties to the Tsunami Warning Service of the National Oceanic and Atmospheric Administration, the Nuclear Regulatory Commission, the Bureau of Reclamation, and various elements of the Departments of Defense, Energy, and Transportation.

The USGS has worked with the Red Cross and other agencies to prepare Sunday paper inserts on earthquake awareness for San Francisco and Anchorage. A USGS employee wrote the pamphlet "Putting Down Roots in Earthquake Country" which was published and distributed throughout southern California by FEMA, the State of California, the Red Cross, and the Southern California Earthquake Center.

Promoting the International Exchange of Earthquake Information and Research. Since the beginning of NEHRP, USGS has had formal, active scientific exchange programs with Russia, Japan, and the Peoples Republic of China. In prior years, before development of the Internet and the demise of the Cold War, these exchanges were rather stiff and prescribed with formal annual meetings at which details of joint research projects were negotiated. The annual meetings continue, but in addition to them there is a continual flow of information, ideas, and results between participants on all sides through electronic mail and personal visits. The USGS also has exchange programs with institutes in France, Italy, Turkey, Mexico, and Canada.

In the case of a large, foreign earthquake, when there are lessons to be learned that have applications in the United States or when assistance is requested, the USGS will send teams of scientists to carry out post-earthquake investigations. During the 25 years of NEHRP the USGS has sent teams to investigate earthquakes in dozens of countries including Algeria, Armenia, Australia, Chile, China, Columbia, El Salvador, Guatemala, Italy, India, Japan, Mexico, Turkey, Yemen, and Yugoslavia. Most of these investigations have led to scientific reports that are provided to the host country and many have led to extensive collaborative work between USGS and foreign scientists.

SIGNIFICANT ACHIEVEMENTS OF NEHRP

The USGS has made substantial progress in earthquake awareness, preparedness, and safety during the past 25 years. Immense efforts have gone into planning earthquake emergency response, retrofitting existing structures, and ensuring that new structures are built to withstand expected shaking levels. The USGS has contributed to these efforts through its hazard assessment, monitoring, and research efforts.

Earthquake Hazard Assessment. The flagship product of the USGS under NEHRP is the series of national seismic hazard maps. These seismic hazard maps are the scientific basis of seismic provisions in building codes enacted throughout the U.S. to prevent loss of life and limit damage during large earthquakes. Ten years ago these code maps were based on four broad, qualitative zones that were used to describe the earthquake hazard nationwide. This depiction and classification of the nation´s earthquake hazard was completely inadequate. Today these maps consist of 150,000 grid points each with a quantitative estimate of the expected shaking at each point. The 1996 national seismic hazard maps are directly included in design maps in the NEHRP Recommended Provisions, published by the Building Seismic Safety Council and FEMA. In turn, these Provisions are used in the 2000 International Building Code (IBC), which is the merging of the three major national model codes. The IBC and the International Residential Code have now been adopted by jurisdictions in 37 states. Thus, this NEHRP product, the set of national seismic hazard maps, is being used to make billions of dollars of new construction each year safer from earthquakes.

The national seismic hazard maps are also used in the FEMA retrofit guidelines, ensuring that older buildings are strengthened so that they withstand future earthquakes. These maps and associated products are also used in the design of highway bridges, landfills under EPA regulation, and dams, as well as the setting of earthquake insurance premiums and the cost of re-insurance. The California Earthquake Authority uses the seismic hazard maps for California, produced by USGS and the California Division of Mines and Geology, to set earthquake premiums for the state earthquake insurance program. Pension funds apply these maps, made under NEHRP, to evaluate the risks to their portfolios of properties. Presidential executive orders specify that new and leased federal buildings must adhere to the NEHRP Recommended Provisions. The state of Oregon recently upgraded to seismic zone 4 along the southern part of its coast, largely based on hazard information presented in USGS seismic hazard maps.

Another major advance in hazard assessment work occurred in the 1990´s when USGS created formal field offices in Pasadena, Memphis, and Seattle. The purpose of these field offices was to bring our scientists in direct contact with the regional users of the results of our studies. Personnel at these field offices, and at our regional center in Menlo Park, California, have been very successful in working with local interests and creating products that will allow these interests to effectively and efficiently address their earthquake risks.

Earthquake Monitoring and Notification. The USGS has also realized major improvements in its ability to provide timely and informative earthquake reports and information. Twenty-five years ago basic earthquake data processing (location and magnitude determination) was done by hand. Scientists made measurements on paper seismograms with rulers and used slide rules to compute epicenters and magnitudes. Earthquake notification was performed by individually dialed telephone calls. It took at least an hour to develop the photographic paper that recorded the seismic data, make the measurements, analyze the data, and make the phone calls. This was the time required to process one earthquake! Today digital data flows from hundreds of seismometers over dedicated communication links to regional and national data centers. At these centers computers that "read" the seismograms using complex analysis programs process the data. Epicenters and magnitudes are generated automatically and instantaneously and the results are broadcast within seconds.

The concepts underpinning the Advanced National Seismic System are allowing USGS to capitalize on the revolution in information technology of recent decades to achieve dramatic advances in real-time seismic data analysis and rapid earthquake notification. The most noteworthy result of this is the "ShakeMap" product. Complementing ShakeMap is a suite of other real-time earthquake products such as earthquake paging and e-mail services, real-time earthquake location maps, automatic Web pages for significant events, and aftershock probability estimators. Recently we established a Web-based interface to provide Internet users with a means of recording individual earthquakes experiences and compiling these into summary maps of shaking intensity ("Did-You-Feel-It?"). These additional products provide rapid, reliable, and comprehensive information about U.S. and worldwide earthquakes.

Understanding Earthquake Processes and Effects. Progress made in earthquake hazard assessments during the past 25 years have their roots in pioneering USGS field, laboratory, and theoretical research focused on understanding the basic physical processes of earthquakes. Key results include:

• Improved models of seismic energy attenuation as a function of distance from an earthquake;
• Use of the Global Positioning System (GPS) to determine the rate at which faults are being "loaded" (stressed) by the movement of tectonic plates that make up the Earth´s outer shell;
• Discovery and documentation of large, prehistoric earthquakes through a new field of study known as paleoseismology through identifying evidence of past earthquakes in trenches dug across faults, in riverbanks, and from drowned coastlines;
• Quantifying the effect of soils and near-surface conditions in amplifying strong ground motion; and,
• Advances in earthquake forecasting through improved understanding of the physics of fracture and friction of rocks in fault zones.

IMPROVING NEHRP

The USGS believes that, although the coordination between NEHRP agencies is good, it could be substantially improved. Coordination between USGS and NSF on NEHRP matters takes place more on a collegial basis, rather than being driven by NEHRP; however, FEMA has recently taken steps to establish a Research Coordination Committee, which may improve the overall coordination. The USGS believes that stronger direction to the overall NEHRP program would be constructive. Because of provisions in the last legislation authorizing NEHRP, USGS now benefits from the advice and guidance of its Scientific Earthquake Studies Advisory Committee. This committee has proven invaluable in providing sound direction to our NEHRP activities. The USGS suggests that a similar advisory body to the entire NEHRP effort would provide the stimulus and guidance to ensure greater coordination, cooperation, and planning.

NEHRP CHALLENGES AND USGS PLANS

Although much has been accomplished under NEHRP, much work remains to be done to ensure safety and reduce economic losses in future earthquakes. The country´s population and economy continue to grow in earthquake prone areas. Exposure to earthquake risk continues to increase. Emergency officials, lifeline managers, the news media, and the public expect immediate, reliable, and complete information on the location, magnitude, impact, and effects of any and all earthquakes.

Earthquake hazard information used in model building codes is applied for public safety only; that is to keep the structure from collapsing. The building may be a total loss, but the inhabitants are expected to be safe. Financial and engineering interests are now pursuing the more sophisticated, and more complicated, concept of performance-based design. Under this concept, the structure is designed and constructed so that it will meet a desired performance level during and after an earthquake. For example, the owners and occupants of a structure housing a national corporate headquarters may want it designed so that it will be completely functional immediately after a strong earthquake. Performance based design concepts require more extensive and complete data on the nature and variation of ground shaking and building from earthquakes.

Going forward, USGS will continue to build on existing USGS earthquake monitoring, assessment, and research activities with the ultimate goal of providing the Nation with earthquake products that promote earthquake mitigation and facilitate earthquake response. At the heart of this effort will be a continued emphasis on delivering information that is useful, accessible, and easily understood. By working closely with policymakers and emergency planners, USGS will ensure that they have the most reliable and accurate information possible about earthquake hazards and that our products are tailored to their needs. The USGS will participate in local and national earthquake mitigation planning exercises and help train emergency responders, contingency planners, risk managers, the media, and others in how to use earthquake hazard assessments and real-time information products. The USGS will also continue to work directly with communities to help them understand their vulnerabilities to earthquakes and to plan mitigation actions. Critical decisions for earthquake preparedness and response, including continued corporate and government operations, are often made far from areas of high seismic hazard. So that informed and appropriate actions can be taken, USGS will continue to work to ensure that earthquake hazard information and products are useful and familiar to decision makers even in regions of low seismic hazard.

Advanced National Seismic System. The ANSS initiative is intended to contribute to reducing loss of life and property in earthquakes through monitoring actual ground shaking levels in urban areas and the dynamic performance of structures and lifelines in earthquakes. ANSS is intended to collect this information through a nationwide network of sophisticated shaking monitors, placed both on the ground and in buildings in urban areas in seismically active regions. Under the ANSS initiative, USGS had added 400 new seismometers in urban areas and 18 new seismometers to the regional networks it supports.

One component of ANSS is the instrumentation of buildings. To date, two buildings have been instrumented under the ANSS initiative. Currently, the spacing of seismometers is not sufficient to correlate the ground shaking to the performance of specific buildings. If hundreds of buildings in high-risk areas are instrumented with seismometers, engineers can determine how specific types of buildings respond to earthquake shaking. Although model building codes set earthquake resistant standards for broad, general classes of structures (i.e. wood frame, residential) on a generic soil type, these instruments will provide data about how more complicated buildings (i.e. steel-moment frame and non-ductile concrete frame) buildings perform during earthquakes and how to design buildings that will perform well during violent shaking.

The instrumentation of structures in seismically active areas provides engineers with critical information they need to determine how buildings respond to earthquakes. This information includes:

• the coupling between the building foundation and the underlying soils;
• the role of torsion of columns in building shaking;
• the performance of commonly used systems such as shear walls combined with a moment-frame structure; and,
• the ability of mathematical models to predict the performance of buildings during strong shaking.

The closely spaced seismometers could also be used to identify areas of special engineering problems, such as high amplification and focusing, that will require special building design before the destructive earthquake occurs. This in turn will allow identification of locations where seismic strengthening of buildings is needed the most, ensuring the cost effectiveness of the mitigation.

A goal of ANSS is improved reliability, timeliness, and breadth of USGS real-time earthquake products for emergency response purposes. ShakeMap, in particular, requires access to a modern seismic network with digital strong motion recording capabilities and real-time telecommunications feeds. Few U.S. urban areas possess this type of modern technology. For this reason, ShakeMap is currently only available in a handful of cities (Los Angeles, San Francisco, Seattle, and Salt Lake City). We note that the instruments and automatic analysis systems being deployed and developed within the ANSS effort can detect, locate, and determine the severity of large, non-natural events that generate seismic energy, such as explosions and impacts.

Earthquake Warnings. As the ANSS system develops, it will be technically possible, under some conditions, to issue warnings within a few tens of seconds of the initiation of strong ground shaking. The seismic waves that carry strong shaking travel at about 2 miles-per-second. If an earthquake occurs 100 miles outside of an urban area, data from ANSS sensors near the epicenter can immediately be transmitted over robust communication links to a data analysis center. Here the data can be analyzed automatically to determine that a strong earthquake has occurred. This could be done within a few seconds. A warning could then be issued via radio to the urban area that strong earthquake shaking is imminent. The warning would give school children time to get under their desks, allow surgeons time safely pause their procedures (if possible), and provide time to suspend the pumping of toxic materials and other hazardous activities. The USGS is taking the lead in demonstrating this capability; however its implementation must be done in cooperation with local and regional governments.

Integrating essential data for expanded urban hazard assessments -- Most current USGS earthquake hazard assessments are compiled on regional or national scales. These estimates typically are limited to calculating hazards on hard rock conditions as opposed to the actual soil conditions beneath cities and lifelines. At scales needed for urban planning and development, assessments need to account for the amplifying effects of soils and the potential for ground failures, such as liquefaction and landslides.

USGS pilot urban assessments in Oakland, Seattle, and Memphis have shown the usefulness of detailed urban assessments. Central to this effort will be the integration of data on local geology, site conditions, and ground motions needed to produce detailed urban hazard maps. These data integration efforts will require partnerships with state geological surveys and local agencies. As these hazard assessments evolve, they will allow estimates of potential earthquake losses to building stocks and critical lifelines. This is one of the keys to developing cost effective mitigation strategies to reduce future earthquake losses.

Earthquake Hazards in the Eastern United States -- The USGS earthquake program devotes approximately 75% of its resources to work in the Western United States, primarily because the hazard there is greater. However, history demonstrates that a catastrophic quake could also strike a major city in the Eastern United States. Four damaging earthquakes with magnitudes greater than 7 centered in the New Madrid, Missouri, area struck the Mississippi Valley in 1811-1812. Charleston, South Carolina, was devastated by a magnitude 6.7 shock in1886, and a magnitude 6.0 quake struck the Boston area in 1755.

USGS studies show that urban areas in the Eastern United States will incur far greater damage and far more deaths in a quake of a given magnitude than those in the West for several reasons: (1) for the same magnitude earthquake, shaking affects a much larger area, (2) most structures are not designed to resist earthquakes, and (3) population density is high and residents are not routinely educated about seismic safety.

USGS is developing the methods and understanding that could improve our understanding of the earthquake hazard in the East, where the causative earthquake faults are rarely exposed at the surface and the subsurface conditions beneath major cities are poorly documented. More thorough and accurate assessment of the seismic risk faced by major urban centers in the East will reveal the greatest vulnerabilities and serve as key input to evaluate possible mitigation strategies.

Earthquake Hazards in Alaska. Alaska has the greatest exposure to earthquake hazard of any state. Because of the relatively small urban population, many assume the risk is low compared to the rest of the country. However, the impact of a devastating earthquake in Alaska can extend far beyond its borders, both by generating deadly tsunamis and through economic consequences. Alaska is a major source of natural resources for the rest of the Nation, a major transportation and commercial node of the Pacific Rim being the 5th busiest air cargo airport in the world, and of significant importance to national defense.

Capitalizing on new national facilities. As described in the 2003 National Research Council report, Living on an Active Earth: Perspectives on Earthquake Science, continued progress toward evaluating earthquake hazards will increasingly require integrative, physics-based research involving theoretical studies of processes controlling earthquake phenomena, sophisticated numerical modeling, in situ, ground-based, and space-based field observations, and laboratory simulations. Research, data collection, and monitoring facilities developed during the first 25 years of NEHRP are aging and becoming obsolete. Recent and proposed U.S. government investments in a number of major earth science and engineering facilities (e.g., ANSS, the NSF-coordinated EarthScope initiative -- including the Plate Boundary Observatory, USArray, and the San Andreas Fault Observatory at Depth, the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES), and a future interferometric synthetic aperture radar (InSAR) satellite mission) offer, for the first time, the breadth and depth of data required to truly address the physical nature of earthquakes.

The USGS will take advantage of these new data streams to perform earthquake hazard focused experiments on scales never before possible. To improve long-term hazard assessments, USGS will also create region specific earthquake occurrence models that simulate the multiple factors operating in active fault systems. A major goal will be to understand the criteria for the occurrence of earthquakes within a fault system and the impact of one quake on the system through the many processes that transfer stresses. To determine if earthquakes are predictable, USGS will build models of earthquake likelihood, akin to weather forecast models.

Earthquake Prediction. Reliable prediction of the time, place, and magnitude of future earthquake is the "holy grail" of earthquake science. The USGS spent considerable effort on earthquake prediction during the early days of NEHRP (1978-1990). After strong efforts and at least one dramatic failure, based mostly on a phenomenological approach, USGS concluded that earthquake prediction would not be possible without a foundation based on a complete understanding of earthquake physics and processes. During the past decade, we have seen considerable progress in the understanding of earthquake processes. This progress in understanding could contribute to advancing reliable earthquake prediction. But, in order to do so, it would be necessary to review the current state of knowledge, identify the scientific problems that should be addressed, and develop a strategy to address these issues.

CONCLUSION

After 25 years of NEHRP, USGS has become a world scientific leader in seismic hazard studies. In implementing the results of these studies to mitigate the effects of earthquakes, USGS has actively collaborated with state geologic surveys, emergency response officials, earthquake engineers, local government, and the public. This has resulted in dramatic improvement in building safety and earthquake response in the United States. But there is still much to be done. By integrating USGS earthquake information with data from new national initiatives, such as ANSS, USGS will be able to develop a new generation of effective and efficient earthquake hazard assessment and mitigation tools. These tools will be used to further reduce losses of life and property in the future earthquakes that are certain to strike our Nation´s seismically hazardous regions.

Thank you, Mr. Chairman, for the opportunity to submit this statement.