Relationship between seismic activity and reduction in pore pressure?

Answer 1

With the increased interest in geothermal energy and injection wells, there has been a great deal of recent research on the relationship between pore pressure and seismicity. There is evidence for a correlation between an increase in pore fluid pressure and an increase in micro seismicity (approximately M_L <2), and the mechanism for this effect is thought to be related to how an increase in the pore fluid pressure will override the resistance to slip along the fault that is caused by friction. However the direct relationship between the magnitude of seismic events and pore pressure is harder to figure out. There are a ton of variables to consider here (e.g. far-field forces, alteration of the wall rock by previous faulting).