ing major centers to promote interdisciplinary collaborations and deliver new products for seismic hazard analysis (110). The primary participants in these programs have been geoscientists, with engineers relegated to a relatively minor role. The Federal Emergency Management Agency leads NEHRP and holds the federal responsibility for seismic risk mitigation. Although FEMA is deeply involved in both risk assessment and emergency management, it is primarily a user, not a coordinator, of earthquake research. At present, no agency or organization is responsible for ensuring an integrated approach to earthquake science and engineering. This vacuum could be filled through structured collaborations between the science and engineering research centers, explicitly funded and frequently reviewed by NEHRP agencies. These collaborations should involve economists and social scientists with expertise in mitigation issues.

Scientists also need better organizational and technological support for communicating with all levels of society about earthquake hazards, mitigation measures, and the appropriate use of earthquake information. The challenges are to select the right kinds of educational activities, target the appropriate audiences, and present them at the right places and times. Appropriately, NEHRP agencies are now placing more emphasis on efforts to interpret scientific research and reduce the results to understandable, usable products. Even if well-packaged, however, such products cannot be “simply thrown over the wall” for public consumption. Effective communication between researchers and end users requires a two-way, continuing dialogue with repeated opportunities for the exchange of ideas and plans. Likewise, effective public education requires interactive mechanisms that can engage an audience at an appropriate level. The new technologies of the Internet—interactive web pages backed by powerful, simple-to-use query languages and digital libraries with up-to-the-minute earthquake information—offer considerable promise. However, their utilization will depend on support structures with more financial and human resources than a typical research group.



As described in Section 1.2, the warning times for destructive tsunamis that cross wide ocean basins can be several hours or more.


Secondary hazards also include fires, dispersal of nuclear materials, and other threats indigenous to the built environment.


The displacement across the fault scales with the cube root of seismic moment for earthquakes of magnitude less than about 6.5 and with the square root of moment for larger events.


A complete discussion of these complexities is given in R.S. Yeats, K. Sieh, and C.R. Allen, The Geology of Earthquakes, Oxford, New York, 568 pp., 1997.


Throughout the engineering literature, the redundant term “time history” is used to describe ground motion as a function of time and is thus synonymous with seismogram,

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