Association of Central U.S. Earthquake Consortium State Geologists

The Central U.S. Earthquake Consortium (CUSEC) was established in 1983 with funding provided by the Federal Emergency Management Agency. This original membership consisted of State Emergency Managers.These members recognized that earthquakes are potentially the greatest single event natural hazard in the nation and in the seven-state CUSEC region. The lack of attention given to geologic factors such as soil liquefaction, slope stability, and soil amplification of earthquake forces have always been of concern to CUSEC. In 1992, the State Geologists from the seven CUSEC states (Arkansas, Illinois, Indiana, Kentucky, Missouri, Mississippi, and Tennessee) organized through a Memorandum of Understanding to address these and similar issues. Through funding from the U.S. Geological Survey's National Earthquake Hazards Reduction Program, the Central U.S. Earthquake Consortium State Geologists are assigning amplification values to soils in parts of Arkansas, Illinois, Indiana, Kentucky, Missouri, Mississippi, Ohio, and Tennessee for enhanced ground shaking from earthquake events. Although some data are available to do this work, without coordination, standardization, and cooperation among the CUSEC states, the task of collecting geologic data from individual states and correlating these data across state lines would be a difficult and costly task. This mapped information is being designed to be added to the Federal Emergency Management Agency's computerized Earthquake Loss Estimation Program (HAZUS). HAZUS, which is based on geographic information system (GIS) software, provides communities with mapped estimates of the severity of ground shaking, damaged buildings, casualties, people displaced from homes, damage to transportation systems, disruption of electrical and water utilities, and costs of repair. Several pilot tests by FEMA have shown that the estimates are very highly dependent on the geological information available for the program. This same mapped information is also the basis for building codes as of 1997.

Original 1999 liquefaction map

State and Federal Emergency Management Agency representatives supported the approach of first, preparing small-scale regional hazard maps (1:2,000,000-scale) to link State Emergency Management Agency (SEMA) groups with CUSEC Geologists and to compile and assemble geologic information on near surface sediments from CUSEC states into a common Geographic Information System (GIS) through coordination of all states' efforts. This first product, completed in 1995, was a 1:2,000,000-scale or 1 inch equals about 32 miles, general seismic hazard map for the CUSEC seven-state region. It shows areas where thick, soft soils exist, which are expected to amplify earthquake ground shaking in relation to pipelines and refineries in the Midwest. The second map products are intermediate-scale (1:250,000-scale or 1 inch equals about 4 miles) seismic hazard maps which have proven to be useful by the state emergency exercise planners, who use the map information to produce detailed earthquake damage scenarios used in State earthquake exercises. These maps are twelve 1×2 degree quadrangles which encompass the entire high risk area of the New Madrid Seismic Zone. Each map covers an area of about 7,600 square miles. These maps of soil amplification are critical in producing realistic estimates of damage when using the Federal Emergency Management Agency's Earthquake Loss Estimation Program. These maps may also be used by themselves to indicate relative areas of shaking and areas where liquefaction may occur. These maps were completed in early 1999. The next scale of mapping started in the summer of 1999 at a scale of 1:24,000 in the Project Impact Communities in the Midwest. These communities worked with FEMA, local community leaders and businesses to produce disaster resistant communities. These maps are necessary for local mitigation, zoning, and for other detailed planning proven successful in California.

CUSEC-SG also drafted a charter to establish a CUSEC Earthquake Prediction Evaluation Council for the Midwest. This council is patterned after the National USGS version and is in place to review any earthquake prediction that is brought forward in the Midwest. In 1998 The CUSEC-SG and USGS entered into a Memorandum of Agreement to better coordinate efforts to guide federal and state funded earthquake research in the CUSEC region based on each others strengths. In 1998 a Memorandum of Agreement was also signed with the Institute of Business and Home Safety.