5:15 PM - 6:30 PM
[STT51-P03] Simulation of hypocenter determination of assumed hypocenters by using S-net stations
To understand accuracy of hypocenters determined by S-net, we simulated of hypocenter determination by using travel times from assumed hypocenters to stations of S-net. These hypocenters are assumed in range between 35.5°N and 40.0°N latitude (grid spacing: 0.25°) and 140.5°E and 143.0°E longitude (grid spacing: 0.25°), depth between 5 and 50km (grid spacing: 2.5km). A number of earthquakes are 3971. We calculated travel times from these hypocenters to seismic stations and estimated arrival times of every station. Hypocenters were determined by using the arrival times. Then hypomh program [Hirata and Matu’ura (1987)] was used. Velocity structure of S-net used calculation of travel times and determination of hypocenters was modeled by introducing result of seismic survey for installation of S-net. As the result, 3914 hypocenters were located. We compared located hypocenters with assumed hypocenters. 196 of the hypocenters were difference than assumed hypocenters. Difference in the epicenters and/or in the depth is more than 3km. Hypocenters assumed in land of more than 100km from coast line were not located precisely. It is importance to research range of precise location of hypocenters by S-net because hypocenters far from a seismic network are not located precisely.