Determinación de parámetros focales del temblor de Huajuapan de León, Oaxaca, del 24 de octubre de 1980, usando sismogramas sintéticos de ondas compresionales y un método de inversión linealizada

Abstract

Long period compressional body waves of the Huajuapan de León, Oaxaca, México earthquake (October 24, 1980, mb = 6.6, Ms = 7 .0) have been modeled by using a synthetic seismogram algorithm based on the WKBJ approximation and a linearized inversion method for fitting source parameters. This method results to be efficient and stable in determining the physical parameters of the model. The resulting focal mechanism (cp¡ = 279°, ó 1 = 22°, 71. 1 = -89°, ~2= 100º, ó2 = 68°, i\2 = -89°) corresponds to a normal fault type mechanism similar to the one proposed by Jiménez et al. (1982). The solution indica tes a source depth of 60 km, well correlated with aftershock locations, a seismic moment of 1.2 1027dyne.cm anda rupture time of 13.5 sec. A triangular time function in velocity is sufficient to obtain a good fitting. It indicates a simple rupture history for periods greater than 1 O sec.