Group A, Poster #025, Seismology

Assessing the impact of geothermal energy production on seismicity in the Salton Sea Geothermal Field

Malcolm C. White, Nori Nakata, Verónica Rodríguez Tribaldos, Avinash Nayak, & Patrick Dobson
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Poster Presentation

2022 SCEC Annual Meeting, Poster #025, SCEC Contribution #12150 VIEW PDF
We seek a unified conceptual understanding of seismicity in the Salton Sea Geothermal Field (SSGF) that integrates the effects of geothermal energy production into the context of its seismotectonic evolution. The SSGF is one of the largest geothermal energy resources in the world, with enough estimated power potential to supply more than 1.4 million homes with sustainable energy. It is also a potential major source of lithium, a critical resource for electric-vehicle batteries. Situated in the step-over region between the southern terminus of the San Andreas fault to the east and the northern terminus of the Imperial fault to the west, the SSGF occupies a pull-apart basin where crustal promotes upward migration of mantle-derived magma, which drives the circulation of geothermal brine in shallow sediments. Geothermal energy production in the SSGF began in 1982, and 11 commercial plants operate today. Previous studies exploring the causal relationship between geothermal energy production and seismicity rates in the SSGF by Brodksy and Lajoie (2013) and Trugman et al. (2016) came to somewhat incongruous conclusions. We now seek to clarify the degree to which human activity influences seismicity in the SSGF. To do so, we compare background seismicity rates over the past 50 years with the available history of production and injection activity at wells associated with geothermal energy production. We contextualize the seismicity that occurs within the transtensional tectonic setting in which the SSGF is located. We observe distinct spatiotemporal seismicity patterns, some of which are most easily understood as part of the long-term seismotectonic evolution of the SSGF, and others that are more easily explained by the movement of shallow fluids. We assess the statistical significance of simple linear models relating pump activity to background seismicity rates. Here, we will present our conceptual model integrating our most recent findings.

Brodsky, E. E., & Lajoie, L. J. (2013). Science, 341(6145), 543–546. doi: 10.1126/science.1239213
Trugman, D. T., Shearer, P. M., Borsa, A. A., & Fialko, Y. (2016). Journal of Geophysical Research: Solid Earth, 121(1), 225–247. doi: 10.1002/2015JB012510