![]() ![]() For induced seismicity in the central United States, recent studies assess induced seismic risk by quantifying the damage to and seismic losses for specific building types (Chase et al., 2019) and life safety risks to building occupants (Liu et al., 2019). Risk-based TLSs were proposed by Douglas & Aochi, 2014, in terms of the risk of nuisance, and by Mignan et al., 2015, in terms of damage potential. While the TLS applied at Pohang was only considering magnitude thresholds, it has been proposed to define thresholds in terms of peak ground velocity determined based on levels of motion that could cause damage (Bommer et al., 2006). ![]() Seismicity during the EGS injection had been monitored and injection operation was adjusted when specific magnitude thresholds were exceeded (Kim et al., 2018). A so-called traffic light system (TLS Bommer et al., 2006 Häring et al., 2008 Zoback, 2012) had been applied at Pohang to keep induced seismicity below a threshold magnitude. The possibility of triggering a damaging earthquake, as ultimately occurred, had been largely ignored. Induced seismicity management approaches applied during the Pohang EGS project have come up short, because they focused only on nuisance shaking (Lee et al., 2019). The international investigation (Lee et al., 2019) concluded that a new risk-based approach is needed to inform operators, regulators, and nonexpert stakeholders at risk in a comprehensible and standardized way. As supposed by two early publications (Grigoli et al., 2018 Kim, Ree et al., 2018) the commission concluded that the earthquake was triggered by the 4 km deep high-pressure injection to enhance the permeability of the geothermal reservoir (Ellsworth et al., 2019 Geological Society of Korea, 2019 Lee et al., 2019). The Enhanced Geothermal System (EGS) project was suspended and an international investigation commission led by the Geologic Society of Korea was initiated. The total economic impact was estimated to exceed US$300M by the bank of Korea (Lee et al., 2019). Direct damage only considers losses caused by damaging ground shaking. The earthquake caused one fatality, injured 135 residents, and caused direct damage of US$75M. Risks associated with induced earthquakes are likely to grow in the future as the application of injection technologies grows.Ĭurrently, deep geothermal energy technologies are under renewed scrutiny due to a damaging M L 5.35 ( M w 5.5)earthquake that occurred in November 2017 in Pohang, South Korea. ![]() Application of energy technologies known to induce earthquakes will likely increase in number and scale to supply the growing worldwide energy demand in a decarbonizing world (IEA, 2017). Induced earthquakes pose a seismic risk and are a threat to the continuing license to develop or operate innovative energy options in the future. Geothermal reservoir stimulation, reservoir impoundment, carbon sequestration, gas extraction, hydraulic fracturing, and waste-water disposal have caused problematic earthquakes. Injection, circulation, and storage of fluids can cause earthquakes by altering subsurface stresses on preexisting tectonically loaded faults (NRC, 2013). ![]() The increasing number of damaging earthquakes induced by application of industrial energy technologies demonstrates the need for a standardized way to effectively assess, communicate, and manage associated risks (Ellsworth, 2013 Grigoli et al., 2017 Gupta & Baker, 2019 Keranen & Weingarten, 2018 Langenbruch et al., 2018 Petersen et al., 2018 Walters et al., 2015). ![]()
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