Engineering characterization of earthquake strong ground motions with applications to the Pacific Northwest

Abstract

This paper is one of a series dealing with earthquake hazards of the Pacific Northwest, primarily in western Oregon and western Washington. This research represents the efforts of U.S. Geological Survey, university, and industry scientists in response to the Survey initiatives under the National Earthquake Hazards Reduction Program. Subject to Director's approval, these papers will appear collectively as U.S. Geological Survey Professional Paper 1560, tentatively titled "Assessing and Reducing Earthquake Hazards in the Pacific Northwest." The U.S. Geological Survey Open-File series will serve as a preprint for the Professional Paper chapters that the editors and authors believe require early release. A single Open-File will also be published that includes only the abstracts of those papers not included in the pre-release. The papers to be included in the Professional Paper are: Implementation Kockelman, William J., "Techniques for reducing earthquake hazards--An introduction" Booth, Derek B. and Bethel, John, "Approaches for seismic hazard mitigation by local governments~An example from King County, Washington" May, P.J., "Earthquake risk reduction prospects for the Puget Sound and Portland Areas" Perkins, J.B. and Moy, K.K., "Liability for earthquake hazards or losses and its impacts on Washington's cities and counties" Preuss, Jane

Stochastic Modeling of California Ground Motions

“…to two alternative simulations; these are the ground-motion relations for the Brune (single-corner-frequency) 80-bar source model (as described earlier), and the stochastic finitefault simulations made using the alternative methodology of Silva et al (1990). The stochastic simulations of Silva et al are very similar in concept to those presented here, but were generated using somewhat different assumptions regarding fault dimensions, subfault size, rise time, and attenuation, as described by Schneider et al (1993).…”

“…They agree well with empirical regression equations (e.g., Abrahamson and Silva, 1997;Sadigh et al, 1997) in the magnitude-distance ranges that are well represented by the strong-motion database. The stochastic ground motion relations are underpinned by a source model that has been validated for earthquakes from magnitudes 4 through 8 (e.g., Silva et al, 1990;Schneider et al, 1993;Silva and Darragh, 1995;Beresnev and Atkinson, 1997, 1998a, 1998b. The attenuation model is derived from regional seismographic data over distances of hundreds of km (Raoof et al, 1999).…”

“…The proposed relations are in good overall agreement with the empirical ground-motion relations within the magnitude-distance ranges that are well represented in the strong-motion database. Finally, we also show that groundmotion predictions from two commonly used stochastic finite-fault methods, those of Silva et al (1990;Silva and Stark, 1992;Schneider et al, 1993) and Beresnev and Atkinson (1997;1998a,b; are approximately equivalent, despite differences in the details of the model formulation.…”

“…An alternative approach would be to treat the soil response analytically, by propagating the rock motions through a specified soil column, using an equivalent linear soil response methodology. Such an approach is most useful in site-specific analyses (e.g., Silva et al, 1990), and has also been proposed for defining generic amplification functions in California (Ni et al, 1999).…”

“…The methodology has been described by Schneider et al (1993) and Atkinson (1997, 1998a). The computations are made with the FINSIM computer code (Beresnev and Atkinson, 1998a), and results are checked against those made with the finite-fault code of Silva (Silva et al, 1990;Silva and Stark, 1992;Schneider et al, 1993).…”