Cua, Georgia and Heaton, Thomas H. (2009) Characterizing Average Properties of Southern California Ground Motion Amplitudes and Envelopes. Earthquake Engineering Research Laboratory, Earthquake Engineering Research Laboratory , Pasadena, CA. (Unpublished) http://resolver.caltech.edu/CaltechEERL:EERL-2009-05
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We examine ground motion envelopes of horizontal and vertical acceleration, velocity, and filtered displacement recorded within 200 km from southern California earthquakes in the magnitude range 2 < M ≤ 7.3. We introduce a parameterization that decomposes the observed ground motion envelope into P-wavetrain, S-wavetrain, and ambient noise envelopes. The shape of the body wave envelopes as a function of time is further parameterized by a rise time, a duration, a constant amplitude, and 2 coda decay parameters. Each observed ground motion envelope can thus be described by 11 envelope parameters. We fit this parameterization to 30,000 observed ground motion time histories, and develop attenuation relationships describing the magnitude, distance, and site dependence of these 11 envelope parameters. We use these relationships to study 1) magnitude-dependent saturation of peak amplitudes on rock and soil sites for peak ground acceleration, peak ground velocity, and peak filtered displacement, 2) magnitude and distance scaling of P- and S-waves, and 3) the reduction of uncertainty in predicted ground motions due to the application of site-specific station corrections. We develop extended magnitude range attenuation relationships for PGA and PGV valid over the magnitude range 2 < M < 8 by supplementing our dataset of S-wave envelope amplitudes with the Next Generation Attenuation (NGA) strong motion dataset. We compare extended magnitude range attenuation relationships with the Campbell and Bozorgnia (2008) and Boore and Atkinson (2008) NGA relationships. Our extended magnitude range attenuation relationships exhibit a stronger inter-dependence between distance and magnitude scaling. This character of ground motion scaling becomes evident when examining ground motion amplitudes over an extended magnitude range, but is not apparent when considering data within a more limited magnitude range, for instance, the M>5 range typically considered for strong motion attenuation relationships.
|Item Type:||Report or Paper (Technical Report)|
|Additional Information:||We wish to thank David Boore and Kenneth Campbell for providing and answering questions about their NGA models, Julian Bommer for providing preprints of his manuscripts, David Wald for interesting and informative discussions on attenuation relationships and help with the ShakeMap codes, and Egill Hauksson for the extensive use of his computers for running the neighborhood algorithm inversions. We also wish to thank John Clinton for his suggestions on improving early versions of the manuscript. This work was supported at various stages by the George W. Housner Fellowship at the California Institute of Technology, the Puerto Rico Strong Motion Program, and the Swiss Seismological Service at the Swiss Federal Institute of Technology (ETH Zurich).|
|Group:||Earthquake Engineering Research Laboratory|
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|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Carolina Sustaita|
|Deposited On:||09 Jun 2015 15:49|
|Last Modified:||09 Jun 2015 15:49|
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