A century of oilfield operations and earthquakes in the greater Los Angeles basin, southern California

Egill Hauksson, Thomas H. Goebel, Jean-Paul Ampuero, & Elizabeth S. Cochran

Published August 16, 2015, SCEC Contribution #2072

Most of the seismicity in the Los Angeles basin (LA basin) occurs at depth below the basin sediments and is caused by transpressional tectonics related to the big bend in the San Andreas Fault. However, some of the seismicity could be associated with fluid extraction and injection in oilfields that have been in production for almost a century and cover ~17% of the area of the LA basin. To evaluate the influence of industry operations, we analyze seismicity characteristics, including normalized seismicity rates, focal depths, and b-values, but find no significant difference in seismicity characteristics within compared to outside of oilfields. We further investigate whether induced events, located within perimeters of the LA basin oilfields, should be expected by 1) comparing current production practices with historical cases of damaging subsidence and earthquakes in the LA basin, 2) examining whether the maximum magnitudes of induced events correlate with total injected volumes, as suggested by previous studies, and 3) similarly examining if maximum magnitudes of earthquake epicenters exhibit an increase with extraction volume. Overall, we find that the management of balanced production and injection of fluids in the LA basin oilfields appears to reduce the risk of induced earthquake activity.

Hauksson, E., Goebel, T. H., Ampuero, J., & Cochran, E. S. (2015). A century of oilfield operations and earthquakes in the greater Los Angeles basin, southern California. The Leading Edge, 34(6), 650-652,654-656. doi: 10.1190/tle34060650.1. http://dx.doi.org/10.1190/tle34060650.1

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