Predicting the Seismic Hazard Due to Deep Injection Well-Induced Seismicity

Disposal of flow-back and produced waters in deep injection wells is known to induce earthquakes in a small number of cases. While many of these induced earthquakes are small (less than moment magnitude [MW] 5), some are in the MW 5 to 6 range and, potentially, can be a significant contributor to seismic hazard at a nearby site. Assessing seismic hazard from disposal-induced earthquakes is complicated by uncertainties in the characteristics of the events. Probabilistic seismic hazard analysis (PSHA) provides a way to incorporate these uncertainties. As a first step, this paper identifies some issues in characterizing disposal-induced seismicity for PSHA and discusses approaches that may be used to address them. Issues discussed are characterization of the rate of recurrence, maximum magnitude, ground motion prediction, and focal depth.