Stress Drop, Seismogenic Index and Fault Cohesion of Fluid-Induced Earthquakes

Abstract Sometimes, a rather high stress drop characterizes earthquakes induced by underground fluid injections or productions. In addition, long-term operations in the can influence seismogenic reaction of rock per unit volume involved. The index is quantitative characteristic such reaction. We derive relationship between and drop. This shows that increases with average seismicity. Further, we formulate simple general phenomenological model earthquakes. both decrease fault cohesion during earthquake rupture process an enhanced level effective stresses could lead to Using these two formulations, propose following mechanism increasing seismicity rates observed, e.g., gas production at Groningen. Pore pressure depletion systematic increase (and thus, magnitudes) due gradually destabilizing cohesive faults stresses. Consequently, elevated index. seismic risk operation time reservoir.