Second-moment approximation of the earthquake source and fault plane identification

The possibility of identifying the fault plane in the case when the source of an earthquake is described in the second-moment-based approximation is analyzed. The commonly occurring type of the earthquake source whose major axis and rupture propagation are directed along the strike axis is analyzed in detail. The possibility of identifying the fault plane of this source depending on the focal mechanisms of the earthquake is explored. The inferred conclusions are verified by the results obtained for two strong earthquakes: the Chilean earthquake that occurred in Maule on February 27, 2010 and the Sumatra offshore earthquake of April 11, 2012.