Fundamental principles of water causing earthquakes and preliminary estimation of the risk of water-caused earthquakes for the Yantan hydropower station

Abstract

This paper introduces a new explanation on the mechanism of water earthquakes, which is different from the conventional water-induced earthquake mechanism. The change in crustal surface water and underground water would enforce underground rock to accumulate enough energy and hence, result in an earthquake without the aid of tectonic stress. The authors call such an earthquake a water caused earthquake. Fundamental instructive principles for predicting the risk of water causing an earthquake will be given in this paper. The region where the water changes can be divided into four tectophysical units i.e. energy-carrier zone, energy-accumulating zone, relatively stable zone and base of buoyance. According to the conditions of these tectonophysical units, it is possible to predict the maximum magnitude of earthquake and epicentre location. The formula for computing the maximum possible magnitude for water caused earthquakes will be given. The authors introduce general characteristics of geology, tectonic geology and hydrogeology of the Yantan reservoir. Using the prediction method suggested in this paper, the authors obtained the following conclusions about the Yantan reservoir i.e. the possible maximum magnitude of water causing earthquake will be close to, or smaller than five. The location of the epicenter will be in the vicinity of the Dong Shan Fault or in the vicinity of fault zone to the north of Ba Ma, which is parallel to Dong Shan Fault.