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Abstract:
In recent decades, the magnitude and harm of injection-induced earthquakes (IIE) due to anthropogenic activities have gradually increased, which has evolved into a global problem. However, the triggering mechanism of induced earthquakes is complicated, and there are significant spatial differences and time delays between the pumping areas and the areas where the induced earthquakes are concentrated, not all injections induce earthquakes, and it is not uncommon for regions with strong injections to remain seismically silent. To explore the controls on IIE, we compare geodetically derived tectonic strain rates with seismicity in Oklahoma where injections are prevalent. Results demonstrate that induced earthquakes are high in areas with moderate tectonic strain rates, while areas with high seismic moment release are consistent with areas with moderate tectonic strain rates, indicating that the regional tectonic is the fundamental cause of IIE. Moreover, the moment rates released by induced earthquakes approach even exceed the tectonic moment rate in the IIE-rich zone. We thus argue that injections indeed causes a large number of induced earthquakes and local seismic hazard in the short term, but limits the potential for larger future earthquakes by depleting the shallow tectonic moment.
