Evaluating non-stationary seismic hazard for gas fields in The Netherlands

Abstract

The seismic hazard due to induced seismicity was evaluated for gas fields where a time-depended seismicity was identified. This analysis was performed using a classical Probabilistic Seismic Hazard Analysis (PSHA) (Cornell, 1968) approach. The PSHA allows defining the state-of-art of current knowledge with regard to about 20 years of induced seismicity. On the other hand a classical PSHA approach is based on a stationary Poisson model probably not appropriate to describe the time varying induced seismicity. To overcome this limitation it is possible to define different time windows in which the stationary hypothesis is still valid or use a more general/complex approach using a non-stationary Poisson model. The second option is substituting the constant activity seismicity rate (ë) with a time dependent variable (ë(t)). Both approaches were investigated using seismicity data from exploration fields in The Netherlands.