GROUND MOTION PREDICTION EQUATIONS FOR CUMULATIVE ABSOLUTE VELOCITY (CAV) USING THE PEER-NGA STRONG MOTION DATABASE

Cumulative absolute velocity (CAV), defined as the sum of the absolute acceleration time series, has been shown to be a better predictor of damage than peak ground motion and response spectra parameters. The nuclear industry uses the value of CAV in consecutive one-second intervals in which the acceleration exceeds 0.025g (CAVSTD) as a check on whether to shut down a nuclear power plant when the response spectra exceed the Operating Basis Earthquake (OBE). The value of CAV exceeding an acceleration threshold of 0.005g (CAV5) has been found to be a better parameter than Arias Intensity or peak ground acceleration (PGA) and magnitude for evaluating liquefaction potential of saturated sands. Most recently, CAVSTD has been used to exclude non-damaging ground motions from contributing to the probabilistic seismic hazard analyses (PSHA) of nuclear power plant sites in the central and eastern United States. However, there are very few CAV ground motion prediction equations (GMPEs). To help fill this void, we developed new GMPEs for the geometric mean horizontal component of CAV (CAVGM) based on the strong motion database and functional forms used to develop GMPEs for peak ground motion and response spectra parameters for the PEER-NGA Project. We also developed a prediction equation between a modified version of CAVSTD (CAVS), which includes all of the USNRC ground motion criteria for shutting down a nuclear power plant, and CAVGM using the PEER-NGA database. We consider our CAV relationships to be valid for magnitudes ranging from 5.0 up to 7.5–8.5 (depending on fault mechanism) and distances ranging from 0 up to 100–200 km (depending on magnitude) for shallow crustal earthquakes in active tectonic regions. We found the standard deviation of both of the CAV parameters to be equal to or smaller than those of any ground motion parameter we have studied thus far. Introduction Cumulative absolute velocity (CAV), which is defined as the integral of the absolute value of the acceleration time series, is calculated from the equation (EPRI 1988): Vice President, EQECAT, Inc., Beaverton, OR, USA, kcampbell@eqecat.com Executive Director, PEER, University of California, Berkeley, CA, USA, yousef@berkeley.edu Proceedings of the 9th U.S. National and 10th Canadian Conference on Earthquake Engineering Compte Rendu de la 9ième Conférence Nationale Américaine et 10ième Conférence Canadienne de Génie Parasismique July 25-29, 2010, Toronto, Ontario, Canada • Paper No 1004