SEISMIC POLICY IN KENTUCKY

The National Earthquake Hazard Reduction Program (NEHRP) recommended provisions for seismic regulations for new buildings and other structures were developed by the Building Seismic Safety Council (BSSC). The provisions were endorsed by the Federal Emergency Management Agency and became the recommended policy for new buildings and other structures in the U. S. The provisions also become policy or set the design standard when they are adopted by state agencies and other organizations such as the International Code Council (ICC). The International Code Council adopted the NEHRP provisions and developed the International Building and Residential Codes. The building and residential codes then were adopted by state agencies, local governments, and other organizations, and became building codes, ordinances, and policies. For example, the Kentucky Department of Housing, Buildings, and Construction adopted the 2006 International Building and Residential Codes (IBC-2006 and IRC-2006) that became the 2006 Kentucky Building and Residential Codes (KBC-2006 and KRC-2006). However, these regulations resulted in extreme high design ground motions for buildings, bridges, and other structures in western Kentucky. For example, IRC-2006 would make it cost-prohibited to build a single-family two-story home in Paducah, Kentucky.

Although development and adaptation of the NEHRP provisions are complicated, they began with USGS national seismic hazard maps. These maps are created from probabilistic seismic hazard analysis (PSHA) with data that varies tremendously in quality, amount, and location. However, it was found that the extreme high ground motions predicted by these maps are not consistent with current understanding and observations in the central United States. The national seismic hazard maps are difficult to interpret and contribute to difficulties implementing seismic policy in the Kentucky. It is essential for geologists and seismologists to communicate seismic hazards in a clear and understandable way.