Factors controlling induced earthquakes in Oklahoma

Injection-induced earthquake (IIE) caused by human activities has become a global problem due to the increased magnitude and frequency in recent decades. However, not all injections can induce earthquakes, and it is common for regions with high injections to remain seismically silent. To explore the controls on IIE, we compare geodetically derived tectonic moment rate with seismicity in Oklahoma where injections are prevalent. Results demonstrate that the aggregation zones of IIE coincide well with regions of relatively higher tectonic moment rate, yet the necessary condition for this scenario is that the water-injected volume exceeds 10⁶ m³, indicating that both may be the underlying causes of IIE. Note that moment rate released by IIE can even exceed tectonic moment rate in the IIE-dominated region. This study elucidates the major controlling factors for IIE, which could help us to assess seismic hazards as well as guide the siting of wells.