On the use of explosion records for examining earthquake location uncertainty in Taiwan

Signals from ten explosions were used to examine earthquake location uncertainty in Taiwan. Location errors for explosion sites determined using a relocation process were expressed in terms of statistical measurements for standard errors in the depth (ERZ), the epicenter (ERH), the root-mean-square of the travel time residuals (RMS), and the station coverage gap (GAP). In general, for this study, major factors in location errors resulted from the poor coverage of seismic stations (e.g., a large value of GAP). Using the relationship between location errors and parameters from the explosion location assessment, uncertainties for earthquake locations in the Taiwan region for a total of 384064 events from 1991 to 2011 were evaluated. Offshore regions in southwestern and northeastern Taiwan had larger location errors. For the inland locales, location errors in longitude, latitude, and depth were approximately 3.1 ± 2.7, 1.3 ± 1.6, and 4.6 ± 3.9 km, respectively. The uncertainties estimated from this study could offer a good reference for other related studies.