Geodetic Measurements and Numerical Models of Deformation at Coso Geothermal Field, California, USA, 2004–2016

Abstract

We measure transient deformation at Coso geothermal field using interferometric synthetic aperture radar (InSAR) data acquired between 2004 and 2016 and relative positions estimated from global positioning system (GPS) to quantify relationships between deformation and pumping. We parameterize the reservoir as a cuboidal sink and solve for best-fitting reservoir dimensions and locations before and after 2010 in accordance with sustainability efforts implemented in late 2009 at the site. Time-series analysis is performed on volume changes estimated from pairs of synthetic aperture radar (SAR) and daily GPS data. We identify decreasing pore-fluid pressure as the dominant mechanism driving the subsidence observed at Coso geothermal field. We also find a significant positive correlation between deformation and production rate.

On the role of thermal stress and fluid pressure in triggering seismic and aseismic faulting at the Brawley Geothermal Field, California.

“…1c&d). This observation shows that the subsidence was not driven by pressure depletion, which is often considered a primary subsidence mechanism in geothermal fields [e.g., Reinisch et al, 2020b;Barbour et al, 2016]. Instead, it is more probable that it resulted from thermal contraction, as inferred at the Coso geothermal field [e.g., Im et al, 2021], or from aseismic slip [Wei et al, 2015;Gan and Elsworth, 2014].…”

Structural Controls Over the 2019 Ridgecrest Earthquake Sequence Investigated by High‐Fidelity Elastic Models of 3D Velocity Structures

“…(e.g., Cirella et al., 2018; Hauksson, 2011; Lei & Zhao, 2009; Romano et al., 2014; Teran et al., 2015; Z. Wang et al., 2009). Regional 3D velocity and heat flow models suggest recognizable material heterogeneities around the Ridgecrest fault system (Figure 2), where there is an assembly of granitic outcrops, surficial quaternary deposits, and subsurface heat sources (e.g., Anderson et al., 2013; CGS, 2010; Fialko & Simons, 2000; Hauksson, 2011; Hauksson & Unruh, 2007; Reinisch et al., 2020; Shaw et al., 2015). According to the heat flow data available from the National Geothermal Data System (Anderson et al., 2013; Hauksson, 2011), the Ridgecrest fault system is within a geothermally active area of heat flow up to 117 mWm −2 , and is only 20 km south of the Coso geothermal area where the subsurface heat flow becomes as high as 1,061 mWm −2 .…”