Classification of mechanisms of induced earthquakes: From a view of rock mechanics

The induced earthquake has attracted a lot of attentions in the world recently. The earthquakes induced by fluid injection and extraction, reservoir impoundment and mining/rock removal have been reported, studied and reviewed in a number of literatures. In this paper, from a view of rock mechanics, three fundamental mechanisms are summarized, i.e., the increase of pore pressure, the change of stress, and the change of frictional coefficient. The stimulation of reservoir-related earthquakes and earthquakes induced by fluid injection are sufficiently interpreted by a Coulomb-Mohr failure criterion and effective stress law in the saturated rock. The mining induced earthquakes mainly result from the change of stress. More remarkably, additional physical or chemical effects of fluids may lead to weakening of materials in fault zones owing to stress corrosion.