Introduction to the 2012 Seismic Hazard Workshop

摘要

At the Advisory Committee on Earthquake Hazards Reduction (ACEHR) meeting on November 9-10, 2010 area engineers and geologist made presentations concerning the seismic hazard and policy in the Central U.S. (CUS). During one presentation, it was pointed out that seismic hazard design values in the International Building Code (IBC) (1) and the American Society of Civil Engineers (ASCE) Standard 7-10 (2) were too high; in many cases higher than that of California. It was also pointed out that the National Earthquake Hazards Reduction Program (NEHRP) Provisions Design Map (3), for the 0.2 Spectral Response Acceleration for the U.S., had an S_(DS) point value in Northwest Tennessee of 4.08 g. When this value was compared to the highest value shown for the West Coast, i.e., 1.88 g, the 4.08 g value is more than a factor of two higher, which did not make sense to many engineers and seismologist in the CUS. As a result, the contrasting difference between these S_(DS) values along with other variations in the IBC and ASCE Standard 7-10 between seismic design in the CUS and seismic design on the West Coast led to recommendations presented to the Advisory Committee, some of which were: 1) "The United States Geological Survey (USGS) National Seismic Hazard Maps portray the Central U.S. as a worst case," and 2) "Kentucky should not be placed in a hazard category twice as dangerous as California or China - not reasonable!"