震源深度对烈度衰减关系模型的影响  

Discussion on the influence of focal depth on intensity attenuation relation model

作　　者：任静[1] 张云芝 李志强 黄帅堂 张方浩[3] 谭专条 陈雅慧 李华玥 REN Jing;ZHANG Yunzhi;LI Zhiqiang;HUANG Shuaitang;ZHANG Fanghao;TAN Zhuantiao;CHEN Yahui;LI Huayue(China Earthquake Networks Center,Beijing 100045,China;Earthquake Agency of Xinjiang Uygur Autonomous Region,Urumqi 830011,China;Yunnan Earthquake Agency,Kunming 650224,China)

机构地区：[1]中国地震台网中心,北京100045 [2]新疆维吾尔自治区地震局,乌鲁木齐830011 [3]云南省地震局,昆明650224

出　　处：《地震地磁观测与研究》2023年第2期50-63,共14页Seismological and Geomagnetic Observation and Research

基　　金：2020年地震应急青年基金(项目编号:CEAEDEM202026);2020年中国地震台网中心青年基金(项目编号:QNJJ202012)。

摘　　要：收集整理1970年以来我国大陆地区418次MS≥4.0地震的烈度等震线和震源深度资料,将我国大陆地区划分为西部(西南和西北地区)和东部(东北、华北地区和华中、华南地区)地区,采用最小二乘法,根据Estevad等和卢建旗等的研究,分区建立基于震源深度的2种烈度衰减关系经验统计模型,探讨震源深度对烈度衰减关系模型的影响。分析发现,东部地区Ⅵ度(6度)区和西部地区Ⅶ度(7度)区长、短轴半径的影响结果略有不同。选取2008年以来MS≥5.0地震事件,取6度以上地区地震烈度圈数据,以实际烈度与经验统计模型烈度的比值为指标,验证2种经验统计模型与实际烈度评定结果的吻合程度,结果表明:2种经验统计模型所得烈度变化趋势基本一致,且基于模型的预测烈度值与实际烈度值较为一致。将2种烈度衰减关系经验统计模型与传统椭圆烈度衰减关系模型进行比较,发现经验统计模型更精准。分析认为,2种基于震源深度的烈度衰减关系模型在我国东、西部地区的适用范围参数如下:①西部地区:震级为4.0≤M_(S)≤8.6,震中距为0≤R≤486 km,震源深度为3 km≤H≤74 km;②东部地区:震级为4.0≤M_(S)≤8.0,震中距为0≤R≤476 km,震源深度为4 km≤H≤36 km。This paper collects intensity isoseismal maps and focal depths of 418 MS≥4.0 earthquakes that occurred in the Chinese mainland after 1970.Considering focal depth,the least square method is used to establish two intensity attenuation relationship models for the western part of the Chinese mainland and its subregions(Southwest and Northwest)and the eastern part of the Chinese mainland and its subregions(Northeast,North China,Central China,and South China).We discuss the influence of focal depth on the intensity attenuation relationship model.The two models considering focal depth are used to compare the influence of focal depth on the calculated long and short axis radius ofⅥdegree(six degrees)in the eastern Chinese mainland and the long and short axis radius ofⅦdegree(seven degrees)in the western Chinese mainland.The results of the models are slightly different.We select MS≥5.0 earthquakes after 2008,take the intensity data of larger than six degrees,and use the ratio of the actual intensity value to the model intensity value as an index to verify the agreement between the two empirical statistical models and the actual intensity.The results show that:results obtained by the two methods have the same basic trend.The attenuation relationship of seismic intensity obtained by the two methods is used to assess the intensity value when the actual value is more consistent with the predicted value.Taking the same method and comparing the results with the elliptical intensity attenuation relationship model,it can be seen that the two intensity attenuation relationship models that consider the focal depth in this paper are more accurate than the elliptical intensity attenuation relationship model.This study gives two models of intensity attenuation relationship considering the focal depth.The applicable magnitude range of the seismic intensity attenuation relationship in the western Chinese mainland is surface wave magnitude 4.0≤M_(S)≤8.6,the epicenter distance range is 0≤R≤486 km,and the focal depth range

关 键 词：震源深度 烈度 衰减关系 探讨 

分 类 号：P315.33[天文地球—地震学]