5Hz GPS seismology of the El Mayor-Cucapah earthquake: Estimating the earthquake focal mechanism

Abstract

High-rate (5Hz) GPS records observed in the near field following the magnitude 7.2 El Mayor-Cucapah earthquake that occurred in northern Mexico on 2010 April 4 are compared with broad-band seismograms. The high-rate GPS displacement records are consistent with the twice-integrated strong-motion seismic records in the near field where broad-band seismograms are clipped due to strong shaking. Agreement degrades at distances greater than about 150 km from the epicentre where displacement amplitudes approach the noise level of GPS seismograms. Using high-rate GPS data the focal mechanism of the main shock is estimated and is shown to be consistent with teleseismic estimates. The result is seen as confirmation that high-rate GPS observed at near-field stations can be applied together with teleseismic seismometers to yield better information about earthquake rupture properties and parameters. © 2012 The Authors Geophysical Journal International © 2012 RAS.