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Rupture History of the 1952 Kern County, California Earthquake: Application of Historical Seismic and Geodetic Datasets

Session: Back to the Future: Innovative New Research with Legacy Seismic Data [Poster]

Type: Poster

Date: 4/19/2021

Presentation Time: 11:30 AM Pacific

Description: 

Today we have the ability to resolve details surrounding historic earthquakes through modern analysis of historical datasets. Here, combining reported geodetic observations with a collection of previously unused strong-motion seismic recordings, we conduct a series of inversions to constrain a slip model for the 1952 Kern County, California earthquake (one of the largest events to strike California). Our analysis suggests that the 1952 event initiated with a strike-slip dominant nucleation-event on a low-angle fault plane (strike=49±3°; dip=35±1°; and rake=11±5°) that subsequently triggered an abnormally energetic rupture on a high-angle fault plane (strike = 51°, dip= 75°). Shortly thereafter, the rupture propagated northeast along the White Wolf fault releasing 7.61×10¹⁹ Nm cumulative moment (M_W 7.18) over 23–26 s. The powerful sub-event contained within a 9×6 km patch near the earthquake hypocenter accumulates 6–7 m of slip and releases a significant amount of static stress (average static stress-drop larger than 50 MPa). The majority of moment-release occurs within the southwest portion of White Wolf fault, located between Wheeler Ridge and Comanche Point. The weighted-average rake-angle over this section is 47–57°, which falls between previous results based on individual seismic or geodetic datasets. Investigation into the regional velocity structure reveals that high P-wave and S-wave velocities are coincident with regions of high slip in our model.

Presenting Author: Scott J. Condon

Student Presenter: No

Authors