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2005 - Hardebeck: focal mechanisms from P-wave polarity and S/P amplitude ratios

An earthquake focal mechanism catalog for southern California, determined using a combination of catalog P-wave first motion polarities and S-wave/P-wave amplitude ratios. The S/P ratios were computed during the SCEC-sponsored Caltech/UCSD analysis of the entire waveform catalog (Hauksson and Shearer, BSSA 95, 896-903, 2005; Shearer et al., BSSA 95, 904-915, 2005), and is the most complete set of S/P ratios available for southern California. The focal mechanisms were computed using the focal mechanism technique of Hardebeck and Shearer (BSSA 92, 2264-2276, 2002; BSSA 93, 2434-2444, 2003.) The dataset includes more than 24,000 focal mechanisms for earthquakes occurring 1984 through 2003.

Reference: Hardebeck, J. L. and P. M. Shearer, Using S/P Amplitude Ratios to Constrain the Focal Mechanisms of Small Earthquakes, Bull. Seismo. Soc. Am., 93, 2434-2 444, 2003.

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