processed immediately following an event and broadcast to users, which include emergency response agencies and responsible government officials, utility and transportation companies, and other commercial interests. The parameters include traditional estimates of origin time, hypocenter location, and magnitude, as well as maps of ground motions pertinent to damage assessments. The need for such systems became clear after the 1994 Northridge, California, and 1995 Kobe, Japan, earthquakes. The lack of accurate information on ground shaking in Kobe, for example, delayed the emergency response and resulted in needless damage and casualties (Box 2.4).

Goal: Develop reliable seismic information systems capable of providing (1) time-critical information about earthquakes needed for rapid alert and assessment of impact, including strong-motion maps and damage estimates, and (2) early warning of impending strong ground motions and tsunamis outside the epicentral zones of major earthquakes.

The ANSS, with its planned nationwide network of on-line broadband seismographs and strong-motion sensors, can fulfill some of these objectives. It can provide time-critical information for immediate public safety and emergency response when the dangers of an earthquake, tsunami, or volcanic eruption arise. The delivery of this information will require a coordinated information infrastructure that feeds directly into emergency management systems through robust, secure connections and can take advantage of new communication pathways, including the Internet and the World Wide Web.

A fully implemented ANSS will provide the framework for upgrading regional seismic information systems to real-time warning systems that, in favorable situations, can automatically notify critical facilities of impending shaking tens of seconds before the seismic waves arrive at the site. The implementation of seismic warning systems will depend critically on automated broadcasting and decision making, and the construction and testing of such systems will require extensive collaborations between seismologists and end users. Although the operational responsibilities for seismic information and warning systems correctly reside with the USGS, the participation of regional network operators, whose missions now include public information and education, is essential.


In a rapidly expanding society, it is difficult to balance earthquake risk against the economic expenses and social strictures (regulations and

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