UNDERSTANDING AND MITIGATING EARTHQUAKE HAZARD IN THE CENTRAL AND EASTERN UNITED STATES

The central and eastern United States (CEUS) is subject to rare earthquakes with the potential for devastating amounts of damage and loss. The U.S. Geological Survey’s (USGS) National Seismic Hazard Mapping project is contributing to the mitigation and reduction of our exposure to seismic hazards throughout the United States. The national seismic hazard maps produced by this project are used in public and private decision-making, including land-use planning, engineering design (including building codes), the setting of insurance rates, and other concerns. Recent advances in prehistoric and historic earthquake studies, earthquake monitoring, and the recording of strong earthquake shaking have contributed to our improved understanding of earthquake hazards in the CEUS. In the last decade, studies of the evidence of prehistoric earthquakes in the geologic record (paleoseismic studies) have revealed important information about the recurrence rate of the larger earthquakes in the CEUS, particularly in the New Madrid, Wabash, and Charleston areas. Historic earthquake studies have refined estimates of the size and effects of major historic earthquakes in the CEUS. Improved and continued instrumental coverage, including the continuing installation of the Advanced National Seismic System, clarifies the rates of earthquake occurrence and the location of major faults. Recordings of strong earthquake shaking from the 2001 Bhuj, India, earthquake have corroborated estimates of expected ground shaking for CEUS magnitude 7 and greater earthquakes. Incorporating all these advances into the 2002 USGS national seismic hazard maps ensures that a scientifically current and appropriate understanding of seismic hazard is used in earthquake hazard mitigation and reduction decision-making in the CEUS.