Was the Mw 7.5 1952 Kern County, California, earthquake induced (or triggered)?

Journal of Seismology
By: , and 

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Abstract

Several recent studies have presented evidence that significant induced earthquakes occurred in a number of oil-producing regions during the early and mid-twentieth century related to either production or wastewater injection. We consider whether the 21 July 1952 Mw 7.5 Kern County earthquake might have been induced by production in the Wheeler Ridge oil field. The mainshock, which was not preceded by any significant foreshocks, occurred 98 days after the initial production of oil in Eocene strata at depths reaching 3 km, within ~1 km of the White Wolf fault (WWF). Based on this spatial and temporal proximity, we explore a potential causal relationship between the earthquake and oil production. While production would have normally be expected to have reduced pore pressure, inhibiting failure on the WWF, we present an analytical model based on industry stratigraphic data and best estimates of parameters whereby an impermeable splay fault adjacent to the main WWF could plausibly have blocked direct pore pressure effects, allowing the poroelastic stress change associated with production to destabilize the WWF, promoting initial failure. This proof-of-concept model can also account for the 98-day delay between the onset of production and the earthquake. While the earthquake clearly released stored tectonic stress, any initial perturbation on or near a major fault system can trigger a larger rupture. Our proposed mechanism provides an explanation for why significant earthquakes are not commonly induced by production in proximity to major faults.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Was the Mw 7.5 1952 Kern County, California, earthquake induced (or triggered)?
Series title Journal of Seismology
DOI 10.1007/s10950-017-9685-x
Volume 21
Issue 6
Year Published 2017
Language English
Publisher Springer
Contributing office(s) Earthquake Science Center
Description 9 p.
First page 1613
Last page 1621
Country United States
State California
County Kern County