Inter Event Times of Fluid Induced Seismicity

We show that the temporal occurrence of seismic events induced by borehole fluid injections is a Poissonian process. We demonstrate this by analyzing the distribution of inter event times between successive events induced in six different case studies. We show that during stationary phases of seismicity the occurrence of events follows a homogeneous Poisson process, while the temporal organization of a complete seismic sequence can be described according to a non homogeneous Poisson process. These results prove the independency of fluid induced events. The underlying process leading to seismic events is hence not influenced by the occurrence of an event. Our results build a basis for upcoming seismic risk studies in geothermal and hydrocarbon industry.