Rupture process of the 2011 Lorca earthquake

Abstract

The focal mechanism of the Lorca 2011 earthquake has been estimated from the inversion of the seismic moment tensor at regional and P and SH waveforms at teleseismic distances. Results shown a reverse fault with planes oriented in E-W direction and shallow focus (4km). The rupture process may be explained using a extended fault (circular fracture of 2 km radius) and rupture velocity of 2.2 km/s. From this model we have generated velocity and acceleration synthetic records for a range of distances from 20 to 200 km. From joint inversion of these synthetic and observed data we have identify the WSW_ENE plane as the rupture plane, with the rupture propagating to the WSW. The 2011 Lorca earthquake is an evidence of the complexity of the region, where we have normal (Lorca, 1977), reverse (Mula, 1999 and Lorca 2011) and strike-slip (Bullas (2002, 2005) motions, while the regional stress pattern corresponds to horizontal N-S compression, with the exception of Lorca 1977 shock.