El temblor de profundidad intermedia de Nicaragua del 15 de octubre de 1967(mb = 6.2) ¿temblor de baja caída de esfuerzos?

Abstract

The spectral analysis of the P-wave recorded at stations located at teleseismic distances, allowed the estimation of the focal parameters for the intermediate depth earthquake with epicenter close to the Masaya Volcano and near to Managua, Nicaragua (11.91 °N, 85.98°W, h= 160 km, mb= 6.2). Seismic moment is 2.4 x 1026 dynes-cm; average rupture radius, 29 km; average stress drop, 4.3 bars; average apparent stress, 1.4 bars; and average slip is 6.4 cm. The relative low stress drop obtained suggests the existence of a region of low resistance to shear stresses inside the Benioff zone at depths of the order of 160 km. This might be due to the heat generated by the frequent occurrence of moderate magnitude intermediate depth earthquakes, to dehidration, processes, and the inherited thermal characteristics of the relatively young Cocos plate that reach the Central America trench.