Abstract

Recent studies of anthropogenically induced seismicity have improved our understanding of the causal relationships between earthquakes and industrial activity. Whether larger-magnitude earthquakes can be triggered and how human injection and production of fluids interact with active faults remain poorly understood. The 2017 Mw 6.5 Leyte earthquake nucleated at a depth near the production zone and within 1 km of an actively producing geothermal field in the Philippines. We use satellite radar data to constrain the pre-earthquake ground deformation across the field and the Leyte fault and to determine the coseismic source parameters. From consideration of regional historical seismicity and fluid extraction model constrained by fluid injection and extraction rates, we find evidence suggesting that the mainshock is directly associated with the geothermal production efforts. Our findings demonstrate that the extraction of geothermal power close to active fault zones is capable of triggering damaging earthquakes, a hazard that was previously underappreciated.