基于PMC方法的辽宁测震台网监测能力评估

Assessment of Earthquake Monitoring Capability of Liaoning Seismic Network Based on PMC Method

为获得辽宁测震台网科学准确的监测能力评估结果,分析辽宁及周边地区的地震监测能力时空分布特征,为测震台网的优化提供科学依据。本研究首次将“基于概率的完整性震级”(PMC)方法应用到辽宁测震台网,通过计算获得辽宁地震台网37个台站的单台检测概率、测震台网合成检测概率以及基于概率的最小完整性震级M P。单台检测概率表明:PMC方法能够客观地反映台站对地震事件的检测能力;营口—海城老震区周围的台站对较小震级的地震有较高的检测能力,受台网布局影响,位于辽宁边界地区台站的检测能力较弱。M P时空分布特征显示:辽宁中部沈阳—辽阳—本溪—鞍山—盘锦地区1.5≥M P≥1.2。辽宁南部大连一带监测能力较低M P≥3.0,辽宁西部与河北交界地区3.0≥M P≥2.5,辽宁其他区域2.5≥M P≥1.8。研究结果表明,为进一步提高辽宁地震台网监测能力,需在辽宁东部、东南部建设台站以提高该区域台站密度,在辽宁西部地区建设部分台站和重新规划需要引入的河北共享台站,以提高该区域的台站密度及改善台站空间布局和该区域的监测能力。

To obtain accurate assessment results on the earthquake monitoring capability of Liaoning seismic network,analyze the spatial and temporal distribution characteristics of earthquake monitoring in Liaoning province and its neighboring regions,and provide scientific basis for seismic network optimization,the probability-based magnitude of completeness(PMC)method was first applied to the Liaoning seismic network.To investigate the seismic detection capability of 37 stations in Liaoning seismic network,this research selected the seismic observation report and station information from January 2010 to December 2017.The results show that the PMC method can objectively reflect the capability of stations to detect earthquake events.Stations around the old Yingkou—Haicheng seismic region exhibit higher detecting capability for earthquakes with smaller magnitudes.Given the network distribution,stations at the edge of Liaoning province present lower detecting capability.The spatiotemporal distribution characteristics of minimum PMC(M P)demonstrate the following values:1.2≤M P≤1.5 in Shenyang—Liaoyang—Benxi—Anshan—Panjin area of central Liaoning;M P≥3.0 in Dalian area of south Liaoning;and 2.5≥M P≥1.8 in other areas of Liaoning.The study results indicate that to further strengthen the monitoring capability of Liaoning seismic network,more stations should be constructed in east and southeast Liaoning to increase station density.Furthermore,the introduction of Hebei-shared stations in west Liaoning can increase the detecting capability of the study area.