Construction of regional three-dimensional travel-time tables of first P arrival for China Seismograph Network

Based on the global-scale three-dimensional P wave velocity model LLNL-G3Dv3，regional travel-time table of first P arrivals of 990 seismic stations of China Seismograph Network is calculated and constructed by using FMM software package. The table covers the station-centered area with 20° multiply 20° in horizontal direction and -5.1 km to 80 km in vertical direction. The horizontal interval of travel-time table is 0.2° and the depth interval is 5 km. Accordingly，travel-times can be calculated within the distance of 10° for any source with depth less than 80 km. As a consequence of the construction of the regional three-dimensional first P arrival travel-time table，the prediction of first P arrival time would be much more improved，and it is significant for improving earthquake locations.