Triggering of great earthquakes: calculation and analysis of combined tidal effect of the Moon and Sun

Abstract

The largest part of solid minerals (with the exception of those which are at the earth's surface) is being extracted world-wide by surface and underground mining techniques, with adits, mines and other mine workings being used. A considerable amount of mineral deposits (including oil reservoirs) is located either close to a fault-line or immediately within the zone of high seismic activity. To prevent economic and environmental damage under the effect of an earthquake, thorough seismic monitoring of the area must be performed, as well as the study of all possible mechanisms of an earthquake occurrence. In analysing the trigger effect of moon- and sun-induced tidal forces on seismic activity, six great earthquakes which occurred close to equatorial latitude over the last 15 years have been considered. Based on the positions of the Sun and Moon during the day relative to the point mass, the maps of horizontal, vertical components and vector of gravitational forces per unit mass have been plotted. The developed technique can be applicable to a set of methods to study integration and stress unloading mechanisms at the boundaries of block structures.