Modeling seismicity activity with applications to induced earthquakes
James Dieterich, University of California Riverside
Wednesday, October 2, 2019 at 10:30 AM
- Building 3, Rambo Auditorium
- Keith Knudsen
In nature earthquakes do not occur as independent events on faults that are isolated in time and space. Rather they occur as emergent phenomena from the system dynamics of geometrically complex fault networks. Simulations that integrate rate- and state-dependent fault constitutive properties, fault system geometry and evolving stress conditions from interactions among earthquakes capture many well-established system-level characteristics of earthquakes, and additionally point to some possible regularities of earthquake phenomena that are not particularly obvious from our short historical record of earthquake observations. Two different simulation approaches are being applied to earthquakes induced by changes of effective normal stress from fluid injection. One characteristic of the simulations of possible practical interest is continuation of injection-induced seismicity following shut-in, even as fluid pressures are locally decreasing — this is due to the self-driven, time-dependent character of the earthquake nucleation process. Simulations of injection-induced seismicity, 2006-2017, at the Val d’Agri, Italy oilfield will be presented.