A probabilistic model to evaluate options for mitigating induced seismic risk

Common responses to induced seismicity are based on control of the anthropogenic activity causing the earthquakes, such as fluid injection or withdrawal, in order to limit either the magnitudes of the events or the level of ground motion to within established thresholds. An alternative risk-mitigation option is seismic retrofitting of the more vulnerable buildings potentially exposed to the ground shaking to reduce the risk to acceptable levels. Optimal mitigation strategies may combine both production control and structural strengthening, for which a probabilistic risk model is required that can estimate the change in hazard caused by production or injection variations and the changes in fragility resulting from structural interventions. Such a risk model has been developed for the Groningen gas field in the Netherlands. The framework for this risk model to inform decision making regarding mitigation strategies can be adapted to other cases of anthropogenically induced seismicity.