Fully Dynamic Model for Reservoir Induced Seismicity

Earthquakes are one of the most potent geological hazards. They may cause vital destruction, including casualties and property damage. Fluid plays an important role in the seismic cycle, along with tectonic deformations. Reservoir induced seismicity (RIS) linked to impoundment of artificial reservoirs and their water level changes, is usually characterized by higher magnitudes, compared to other types of natural and anthropogenic fluid-induced seismicity. However, there is still no comprehensive understanding of the RIS mechanisms despite previous high-resolution in-situ water level and seismic monitoring and their statistical analysis. This study suggests a fully coupled poroelastic model for fully dynamic RIS sequences simulations in a faulted reservoir. The model is thoroughly verified (e.g., on quasi-static Terzaghi and dynamic compressive poroelastic seismic wave propagation, and on other problems). Seismic sequence patterns simulated using a rate-dependent frictional contact under extension and with adaptive time stepping demonstrate proper characteristics applicable to tectonic earthquakes. These verifications and benchmarking demonstrate a convincing agreement with analytical predictions. The fluid flow within the rock and over the fault is modeled as well, being enhanced after the activation of a reservoir impoundment. The model allows further investigation of the RIS spatio-temporal characteristics and triggers. It also may allow for improving earthquake prediction and mitigation policy, especially in areas with substantial water level fluctuations.