Obtención de correcciones de estación para redes sismológicas locales; correcciones para la red RESCO de Colima

Abstract

Correct location of seismic hypocenters is essential for microseismicity studies based on local seismological network data. The spatia-temporal distribution of the seismic sources reflects the stress distribution and evolution in volcanos and active faults, and gives important information for hazard assessment. Seismological networks that do locations based on a laterally homogeneous velocity model, particularly when located in regions of abrupt topography, require station corrections for precise hypocentrallocations. A method is presented for obtaining station corrections for local seismological networks, based on a preliminary determination from teleseismic signal arrival times, modified by trial and error and fitting of mean residuals from local earthquake locations. The method is applied to obtaining corrections for the stations of the Colima Seismological Network (RES CO) which monitors the seismic activity of the Fuego Volcano. These corrections range from -0.200 s to +0.360 sand, when applied to the location of 30 shallow volcanic earthquakes, reduce the total hypocentral errors from 0.092 km to 0.063 km, the origin time ones from 0.038 s to 0.026 s, and considerably increase the location stability and robustness.