Simultaneous inversion for local earthquake hypocentres, station corrections and 1-D velocity model of the Jamaican crust

摘要

A new 1-D velocity model for Jamaica has been obtained from the simultaneous inversion of P- and S-wave travel times of well-solved local earthquakes. The crust is modelled as four flat uniform layers with compressional velocities of 5.15 km/s to 4.5 km depth, 6.30 km/s to 9.5 km, 6.60 km/s to 22.0 km and 7.11 km/s to 30.0 km. The upper mantle P-velocity is 7.81 km/s, which is consistent with upper mantle velocities found elsewhere in the Caribbean Basin. The new model reduces significantly the root mean square misfit of the selected data from 0.128 to 0.112 when compared to the best model previously used. In addition, the model solves events to more acceptable focal depths of 10 to 25 km. Station corrections of ?0.20 to +0.06 for P and ?0.75 to 0.13 for S-waves relative to the reference station were obtained. The new model is expected to improve Jamaican earthquake locations particularly in obtaining more reliable focal depths, which in turn will enhance the interpretation and understanding of local seismicity and neotectonics.