Real-time detection and location of local seismic events in central California
Real-time detection and location of local seismic events in central California
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加州中部当地地震事件的实时检测和定位
DOI：
10.1785/bssa0670020433
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发表时间：
1977
影响因子：
3
通讯作者：
S. W. Stewart
中科院分区：
文献类型：
--
作者：
S. W. Stewart
本文介绍了一个用于加州中部地区地震事件自动探测和定位的计算机系统。该系统监测来自美国地质调查局中心加州和奥罗维尔地震网络的108个短周期垂直分量台站。在事件发生后的2到5分钟内，确定位置和震级后，连同首次到达时间一起沿着打印出来。波浪的开始必须是清晰和冲动的，以获得最佳效果。由于这个原因，区域性事件和种族主义通常被拒绝。
对于相对密集的16站奥罗维尔网络，取得了最好的结果。1975年10月，118个人工计时的事件中有107个（91%）也由实时系统计时和定位。另有8起事件（7%）被实时检测到，但没有成功定位。在107个同时提供联机和手动计时位置的事件中，92%的联机位置位于手动计时确定的震中2公里范围内。
1975年10月，实时系统监测了加州中心网络150个站点中的91个。在260个通过手动计时定位的事件中，225个（86%）被实时系统检测到。检测到的事件幅度范围从0.8到2.9。用人工计时方法探测和定位的11/4级及以上的事件中，约有95%也被实时系统探测到。基于人工计时和计算机计时到达的震源位置之间的差异可能在0.1到5分的纬度或经度之间。
A computer-based system dedicated full time to automatic detection and location of local seismic events in central California has been developed. The system monitors 108 short-period vertical-component stations from the U.S. Geological Survey central California and Oroville seismic networks. Locations and magnitudes, when determined, are printed out along with first arrival times, within 2 to 5 min after an event occurs. Wave onsets must be clear and impulsive for best results. For this reason, regional events and teleseisms are usually rejected.
The best results have been obtained for the relatively dense, 16-station Oroville network. For the month of October 1975, 107 (91 per cent) of the 118 events timed by hand were also timed and located by the real-time system. An additional eight events (7 per cent) were detected in real-time but were not successfully located. Of the 107 events for which both on-line and hand-timed locations are available, 92 per cent of the on-line locations are within 2 km of the epicenters determined by hand-timing.
During October 1975 the real-time system monitored 91 of the 150 stations of the central California network. Of the 260 events located by hand-timing, 225 (86 per cent) were detected by the real-time system. Magnitudes of detected events range from 0.8 to 2.9. Approximately 95 per cent of the events of magnitude 1¼ and greater detected and located by hand-timing methods were also detected by the real-time system. Differences between hypocentral locations based on hand-timed and computer-timed arrivals may vary from 0.1 to 5 min of latitude or longitude.