Seismogenic Index of a Reservoir Location Estimated from Tectonic Seismicity and Crustal Deformation

We address the question whether tectonic seismic activity within an area where a fluid injection is planned can be used to evaluate its seismotectonic state. For this purpose, we expand and reformulate the theoretical framework which essentially applies to describe the occurrence of fluid-induced seismicity to the case of tectonic seismicity. Based on this model, we introduce the tectonic seismogenic index which can be determined prior to an injection if the tectonic seismicity rate and the crustal deformation rate are known in the reservoir region. We apply the derived formalism to reservoir locations where the seismogenic index for fluid-induced seismicity had already been obtained. Thus, we can examine whether the two differently defined seismogenic indices are comparable for an injection location. Our results show that the tectonic seismogenic index can be used as a proxy for the seismogenic index of fluid-induced seismicity. Thus, we conclude that our formalism can contribute to avoid the occurrence of large-magnitude fluid-induced earthquakes by properly selecting and developing reservoir locations.