Revisiting historical earthquakes in our backyard: 1925 Santa Barbara and 1952 Kern County

Scott J. Condon

Published August 15, 2018, SCEC Contribution #8820, 2018 SCEC Annual Meeting Poster #080

We revisit the historic 1925 Santa Barbara and 1952 Kern County earthquakes using available seismic and geodetic data. As these two events occurred before the establishment of the World-Wide Standard Seismographic Network, our knowledge is very limited. For the 1925 Santa Barbara earthquake, we have digitized analog Bosch-Omori seismic records from the Berkeley Seismology Lab (BRK) using Teseo, a specialized digitization tool, and corrected for distortion caused by the instrument's mechanical arm. Our preliminary analysis, which treats this earthquake as a point source and the 2013 Mw 4.8 Isla Vista earthquake as an Empirical Greens Function (EGF), leads to a magnitude estimate of 6.4. For the 1952 Kern County Earthquake, our preliminary analysis reveals that the earthquake initiated on a thrust-dominant fault, dipping ~45°, and then migrated to a more energetic rupture with a different focal mechanism, after ~3 seconds. In view of the fact that the available bandlimited strong motion seismic data alone fails to constrain the source process, we are collecting geodetic observations to conduct a joint inversion with the goal of developing a slip model consistent with previous studies.

Citation
Condon, S. J. (2018, 08). Revisiting historical earthquakes in our backyard: 1925 Santa Barbara and 1952 Kern County. Poster Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
Seismology