Evaluating earthquake safety in mid-American communities

This paper reports on research being conducted at the Mid-America Earthquake Center to explore the characteristics of seismic risk for communities in the vicinity of the New Madrid seismic zone. By risk, the product of seismic hazard and community vulnerability is meant. The research focused on two communities, Carbondale, Ill. and Sikeston, Mo., to estimate potential earthquake effects to specific buildings and to identify potential mitigation actions. Buildings were evaluated using ATC-21 rapid visual screening and HAZUS99 was used to estimate earthquake losses for a range of plausible earthquake threats to each community. Vulnerable structure types in the two study areas include unreinforced masonry, reinforced masonry, and concrete frame, which are common among important educational, governmental, residential, and commercial buildings in the two communities. Annualized direct economic losses to buildings are approximately $500,000 per year for each study area. Serious injuries from earthquakes appear to be relatively unlikely for these communities under most earthquake scenarios but may severely strain the capabilities of earthquake-damaged hospitals to provide adequate services. The study underscores the need for a prudent level of mitigation and preparedness in mid-America.