[关键词]
[摘要]
根据福建地震台网的地震目录,利用各个地震事件前4 台的P 波到时对Tnow定位方法和4 台连续定位方法进行检验,结果表明,两种方法的定位结果相差不大,大部分地震事件的定位偏差也都较小; 随震中距的增大,两种方法对网外地震的定位偏差可能增大,这可能和台站集中在震中的一侧、参与定位的台站与地震之间的张角较小有关。波速结构对4 台连续定位方法的定位结果存在一定的影响,选择合适的速度模型将有助于改善地震预警定位结果。采用Tnow定位方法不能定位的地震事件相对于4 台连续定位方法要多,这可能是由于Tnow定位方法应用了未触发台站的信息,而部分P 波到时信息因台站断记或震相记录不清晰等原因而未在地震目录中体现导致的; 综合考虑两种定位方法的局限性有助于提高地震预警系统的稳定性和可靠性。
[Key word]
[Abstract]
According to earthquake catalog records of the Fujian Seismic Network,the Tnow method and the Four Stations Continuous Location method put forward by Jin Xing are inspected by using P-wave arrival information of first four stations of each seismic event. It shows that the two methods for earthquakes within the network can obtain near location results and small location deviations of the majority events. For earthquakes outside the network,the location deviation may amplify as the epicentral distance enlarges,owing to the seismic station distribution which spread toward the side of epicenter and the small opening angle between seismic stations used for locating and epicenter. For the Four Stations Continuous Location method,the impacts of the wave velocity on the location results may be significant for earthquakes outside the network,selecting a velocity model which is similar to actual structure of the wave velocity will contribute to improving location results of earthquakes. The Four Stations Continuous Location method can locate more seismic events than the Tnow method. It concludes that the Tnow method makes use of mistake information from several triggering stations in earthquake catalog,due to discontinuous records or unclear records of seismic phase,which induces incorrect locating,which may due to the fact that the Tnow method makes use of information from stations without triggering.
[中图分类号]
[基金项目]
国家科技支撑计划项目( 2009BAK55B02) 资助