福建台网接入台湾台站对定位台湾中深源地震精度影响分析
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摘要
福建台网负责监测中国台湾地区地震。对于中深源地震使用何种定位方法能获得较好的地震参数,这直接影响到地震定位精度。利用JOPENS系统中交互分析软件MSDP提供的定位方法,对同一地震进行两次定位,即不使用和使用接入的台湾台站,将福建台网得出的两次结果与中国台湾公布的地震参数进行对比,分析定位精度,进而找出适用于台湾地区中深源地震的定位方法,以便进一步判断在地震速报中使用这些台站进行辅助定位的可行性,并给出相关的操作方法及建议。
Focal depth is an important parameter in seismic studies,seismotectonics,seismic risk assessment,and seismic event identification.Its accuracy has an effect on the understanding of focal processes,fault tectonics,and stress fields.Depth from the epicenter to the source of an earthquake is defined as its focal depth and is divided into three categories,i.e.,less than 70 km,between 70 km and 300 km,and greater than 300 km called shallow,intermediate,and deep earthquakes,respectively.Because tectonic plates push into each other,the activities of intermediate and deep earthquakes reflect the driving forces of these plates.Northeastern offshore Taiwan is an active earthquake region because of its location where the Eurasian and Pacific plates meet.Some intermediate and deep earthquakes have seismic phases that are different from shallow earthquakes.Therefore,finding a fast and accurate method for locating intermediate and deep earthquakes is of great importance for rapid earthquake reporting.The Fujian network monitors earthquakes in the Taiwan region.Better seismic parameters in the location methods used for intermediate and deep focus earthquakes would directly affect rapid earthquake reporting.The Fujian network has access to 16 Taiwanese stations.This paper uses the method in MSDP——an interaction analysis software in JOPENS,to locate the same earthquake twice(using the Taiwan stations or not).The results are compared with data on Taiwan's official website to identify appropriate methods for locating intermediate and deep focus earthquakes in the Taiwan region.Finally,we analyze the feasibility of using the Taiwan stations to produce rapid earthquake reports and provide operating methods and recommendations.
Focal depth is an important parameter in seismic studies,seismotectonics,seismic risk assessment,and seismic event identification.Its accuracy has an effect on the understanding of focal processes,fault tectonics,and stress fields.Depth from the epicenter to the source of an earthquake is defined as its focal depth and is divided into three categories,i.e.,less than 70 km,between 70 km and 300 km,and greater than 300 km called shallow,intermediate,and deep earthquakes,respectively.Because tectonic plates push into each other,the activities of intermediate and deep earthquakes reflect the driving forces of these plates.Northeastern offshore Taiwan is an active earthquake region because of its location where the Eurasian and Pacific plates meet.Some intermediate and deep earthquakes have seismic phases that are different from shallow earthquakes.Therefore,finding a fast and accurate method for locating intermediate and deep earthquakes is of great importance for rapid earthquake reporting.The Fujian network monitors earthquakes in the Taiwan region.Better seismic parameters in the location methods used for intermediate and deep focus earthquakes would directly affect rapid earthquake reporting.The Fujian network has access to 16 Taiwanese stations.This paper uses the method in MSDP——an interaction analysis software in JOPENS,to locate the same earthquake twice(using the Taiwan stations or not).The results are compared with data on Taiwan's official website to identify appropriate methods for locating intermediate and deep focus earthquakes in the Taiwan region.Finally,we analyze the feasibility of using the Taiwan stations to produce rapid earthquake reports and provide operating methods and recommendations.
引文
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[2]王周元,何少林,李勇,等.中国中深源地震分布特征及其意义[J].西北地震学报,2000,22(3):288-295.WANG Zhou-yuan,HE Shao-lin,LI Yong,et al.Distribution Feature of Intermediate and Deep-focus Earthquakes in China and Its Significance[J].Northwestern Seismological Journal,2000,22(3):288-295.(in Chinese)
[3]韩京,周仕勇,黄建英,等.新疆地震目录中的中源地震定位问题研究[J].内陆地震,2004,18(2):113-121.HAN Jing,ZHOU Shi-yong,HUANG Jian-ying,et al.Location Study of Earthquakes with Mid-deep Source in Xinjiang Seismic Catalogue[J].Inland Earthquake,2004,18(2):113-121.(in Chinese)
[4]冯建刚,蒋长胜,韩立波,等.1970年以来甘肃台网地震观测报告收集整理及其重新定位研究[J].西北地震学报,2012,34(3):289-293.FENG Jian-gang,JIANG Chang-sheng,HAN Li-bo,et al.Collection and Reestablish Work for the Earthquake Observation Reports of the Gansu Seismographic Network Since 1970and Earthquake Relocation[J].Northwestern Seismological Journal,2012,34(3):289-293.(in Chinese)
[5]陈贵美,刘锦,刘军,等.数字地震台网对不同区域地震事件的震中定位研究[J].华北地震科学,2010,28(1):59-64.CHEN Gui-mei,LIU Jin,LIU Jun,et al.Analysis on Precision of Deferent Earthquake Location Methods in Guangdong Digital Seismic Network[J].North China Earthquake Sciences,2010,28(1):59-64.(in Chinese)
[6]李莹甄,殷娜,李小晗.不同震级标度转换关系研究概述[J].地震工程学报,2014,36(1):80-87.LI Ying-zhen,YIN Na,LI Xiao-han.Review of the Conversional Relationship for Different Magnitude Scales[J].China Earthquake Engineering Journal,2014,36(1):80-87.(in Chinese)
[7]蔡杏辉,曹轶,许振栋.福建与台湾地震台网测定震级偏差浅析[J].防灾科技学院学报,2013,15(3):72-77.CAI Xing-hui,CAO Yi,XU Zhen-dong.Deviation Analysis of Earthquake Magnitude Determination by Fujian and Taiwan Seismic Network[J].Journal of Institute of Disaster Prevention,2013,15(3):72-77.(in Chinese)