SSA 2008 Special Session: Extreme Ground Motions

SSA 2008 Annual Meeting
16-18 April 2008, Santa Fe, New Mexico

Special Session: Extreme Ground Motions

Abstract Deadline, January 11, 2008

Extreme ground motions are the very large amplitudes of earthquake ground motions that can arise at very low probabilities of exceedance, as was the case for the 1998 probabilistic seismic hazard analysis (PSHA) for Yucca Mountain, when extended to hazard levels of 10-6/yr. A five- year effort funded by the Department of Energy is investigating the credibility of such ground motions through studies of physical limits to earthquake ground motions; unexceeded ground motions, as revealed by fragile geologic structures; and frequency of occurrence of very large ground motions or of earthquake source parameters (such as stress drop and faulting displacement) that cause them. Of interest to ExGM, as it has been to earthquake seismology for decades, is why crustal earthquake stress drops are so sensibly constant and so much less than the frictional strength of rocks at mid-crustal depths.

At the halfway point of this project, we invite papers on the subject matters above as well as others that speak to ground-motion amplitudes at hazard levels of 10-6/yr or smaller. Such analyses might include geologic and geomorphic considerations of landscapes that are of the order of a million years old.

Conveners:

Tom Hanks
U.S. Geological Survey, Menlo Park, CA
thanks [at] usgs.gov

Norm Abrahamson
Pacific Gas & Electric Co., San Francisco, CA
naa2 [at] pge.com