Location and Source Parameters of the 19 June 1994 (MW = 5.0) Offshore Petrolia, California, Earthquake
The MW = 5.0, 19 June 1994 offshore Petrolia, California, earthquake was well recorded by nine ocean-bottom hydrophones (OBH) and seismometers (OBS), providing an opportunity to precisely locate an earthquake in the tectonically active Mendocino triple junction region. Adding the offshore data improves the azimuthal station coverage and essentially removes the epicenter's sensitivity to the choice of inversion parameters and velocity models. The hypocentral parameters, assuming an oceanic upper-mantle velocity of 7.9 km/sec, are 10:39:33.2 UTC for origin time, 40.376° N latitude, 124.441° W longitude, and a depth of 18.8 km. The moment-tensor solution obtained by modeling of low-frequency regional waveforms indicates predominantly strike-slip faulting with a north-south-trending P axis, as is typical for Gorda plate earthquakes, and confirms the depth estimate from the P-wave travel-time data.
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Citation / Publisher Attribution
Bulletin of the Seismological Society of America, v. 87, no. 1, p. 272-276
Scholar Commons Citation
Braunmiller, Jochen; Leitner, Beate; Nábělek, John L.; and Tréhu, Anne M., "Location and Source Parameters of the 19 June 1994 (MW = 5.0) Offshore Petrolia, California, Earthquake" (1997). School of Geosciences Faculty and Staff Publications. 827.