2013年岷县M_s6.6地震区域台阵强震动记录衰减与烈度线比较分析  

Strong Motion Records and Attenuation Analysis of July 22,2013,Minxian M_s6.6 Earthquake

作　　者：何新社[1] 刘旭宙[1,2] 潘颖凌 田秀丰[1] 

机构地区：[1]中国地震局兰州地震研究所,甘肃兰州730000 [2]中国地震局地震预测研究所兰州科技创新基地,甘肃兰州730000

出　　处：《地震工程学报》2013年第4期774-779,共6页China Earthquake Engineering Journal

基　　金：中国地震局地震预测研究所基本科研业务专项(20121ESLZ03)

摘　　要：2013年7月22日甘肃岷县6.6级地震是十年来发生在甘肃省破坏性最大的地震.本文对距震中距18～218km以内的22个强震动台所获取的主震记录进行了分析处理,研究了该次地震在强震动台站分布方向上的衰减规律.将根据衰减规律得出的烈度区域与震后灾害评估的烈度图比较后发现,分析得出的Ⅷ度、Ⅶ度区范围相对略大,Ⅵ度以下区域范围则大致相当,其原因应该与近场的强震动记录较少有关系.The Minxian MS6.6 earthquake,the largest earthquake to occur in Gansu province during the past decade,devastated areas in Minxian and Zhangxian and affected counties in Longnan and the Gannan Tibetan Autonomous Prefecture more than 100 km from the epicenter.During the tenth five-year plan,20 strong-motion stations have been erected in southeastern Gansu,most of which recorded the main shock.In addition,several stations in Lanzhou also recorded strong motion.After preliminary processing of the strong motion data,we determined that the majority of stations that recorded the main shock are broadly distributed with same strike; therefore,a simplified mathematical model was developed to analyze the attenuation of these strong motion records,The epicentral distances of the strong motion stations recording the main shock are 18 km to more than 200 km.The largest peak ground acceleration was recorded by the Minxian strong motion station at 172.5 cm/s2 with an epicentral distance of 18 km.For the free-field soil observation conditions,these values essentially reflect the local ground acceleration; therefore,the extent of damage reached Ⅷ°.Stations near Lanzhou with epicentral distances close to 200 km also recorded the motion,with peak acceleration between 1 cm/s2 and 8 cm/s2.Chinese ground motion attenuation data originally used ground motion data observed in the United States as a reference before such information was recorded in China.In recent years,a Chinese digital strong motion observation network was been created to provide important data in earthquakeprone regions for in-depth research of Chinese ground motion attenuation.Therefore,the study of Minxian MS6.6 earthquake ground motion attenuation also has practical significance in areas outside of southeast Gansu.In the study of peak ground acceleration attenuation,the following formula is often used：lg y =c1 ＋ c2 M＋ c3M2＋ c4lg [R ＋ c5exp （c6 M）],…………………… （1）where y is the peak ground acceleration,M is the magnitude,R is the epi

关 键 词：岷县MS6 6地震 强震动记录 衰减 烈度区 

分 类 号：P315.914[天文地球—地震学]