We compared the simulation results given by 3-D and 2-D models using finite element method, which indicates that 3-D computation is more close to theory result. To calculate different factors act on the elastic stress and pore pressure separately, the results show that poorly-constrained diffusivity is the key factor in computation of pressure seepage as well as reservoir-triggered seismicity, while the elastic stress field also have a certain effect on the pore-pressure. Meanwhile, coupling computation is needed between elastic stress field introduced by reservoir loading and water pressure seepage field. Although this coupling effect is not always significant, it is very important to understanding the pattern of reservoir triggered seismicity. We chose Zipingpu Reservoir as an example to calculate the Coulomb stress change and discuss seismicity in detail during the period of storage through seismic relocation. The result indicates the relationship of seismicity and the importance of tectonic stress field on understanding the role of Coulomb Stress Change in triggering devastating earthquakes.
To deeply understand the triggering role of reservoir in seismicity, it is important to compute the Coulomb stress change on the faults with different geometries and mechanical natures produced by the reservoirs, and analyze its correlation with seismicity through precise seismic relocation. With the development of the society, the demands of industrial consumption and agricultural water and domestic water have been increased. However, the impoundment of the reservoir can not only put an enormous compressive stress on the bottom rock of the reservoir area, but also cause an amount of head pressure and pore pressure which could diffuse along fracture zone, faults, fissures and other tectonics structure.
