青藏高原东北缘M_s≥6.0强震活动特征及未来形势研究  

The Activity and Trends of Ms≥6.0 Earthquakes at the Northeastern Margin of the Qinghai-Tibetan Plateau

作　　者：姚家骏[1] 王慧娟[2] 冯建刚[3] 马玉虎[1] 李玮杰[1] 

机构地区：[1]青海省地震局,青海西宁810001 [2]湖北省气象局,湖北武汉430074 [3]中国地震局兰州地震研究所,甘肃兰州730000

出　　处：《地震工程学报》2013年第4期737-742,共6页China Earthquake Engineering Journal

基　　金：2013年度震情跟踪青年课题(2013020105);2012年星火计划青年项目(XH12051Y);青海省工程地震研究院基金(Matlab在工程场地地震安全性评价中的应用)

摘　　要：2013年7月22日甘肃岷县漳县6.6级地震打破了青藏高原东北缘地区自2003年以来近十年的6级平静,该地震的意义及该区未来震情发展受到了地震学家的关注.本文运用Morlet小波变换分析了1875-2013年青藏高原东北缘MS≥6.0强震活动的周期特征,结果表明该区强震存在2～3年、8～10年、25～30年等尺度的显著周期;1977年以来青藏高原东北缘地区强震活动频度虽然正常但活动强度处于一个相对较低的阶段.在讨论了岷县漳县6.6级地震的发震背景基础上,认为该地震在青藏高原东北缘强震活动长时间较弱的背景下发生,可能是该区强震活动强弱的一个拐点,未来该区强震活动的频度与强度有增加的趋势.研究结果对该区震情跟踪工作有一定的参考价值.The northeastern margin of the Qinghai-Tibetan plateau is an earthquake-prone zone,where some MS≥8.0 strong earthquakes have had serious consequences,for example,the 1920 Haiyuan earthquake of magnitude 8.5 resulted in more than 220 000 deaths.The Minxian-Zhangxian MS6.6 earthquake of 2013,which occurred in the northeastern margin of the Qinghai-Tibetan plateau,broke about ten years of seismic quiescence （MS≥6.0） since the Minle earthquake of 2003.The significance of the MS6.6 earthquake and the earthquake tendency has attracted a great deal of attention,because many seismologists believe that the seismic risk in this area increased after the Wenchuan earthquake of 2008.The Benioff strain energy is a physical quantity that can be used to describe seismic activity,and it contains information on the frequency and strength of earthquakes in a given region.Some research on Benioff strain energy has been done to obtain a law for seismic activity.In this article,we calculate the Benioff strain energy of MS≥6.0 earthquakes in the northeastern margin of the Qinghai-Tibetan plateau,and analyze the periodic characteristics of MS≥6.0 strong earthquakes from 1875 to 2013 using the Morlet wavelet method.The results show that there were several main periods of activity,which are about 2 to 3 years,8 to 10 years,and 25 to 30 years,and the first two periods were determined after the significance test was made,From the Benioff strain energy,the frequency of strong earthquakes in the northeastern margin of the Qinghai-Tibetan plateau has been normal since 1977,but the strength is relatively low.Using the effective earthquake case,this paper also discusses the background of the Minxian-Zhangxian MS6.6 earthquake and estimates the postearthquake trend by analyzing the relationship between the probability of earthquake occurrence and the leaving time.The results show that there is a fairly large risk of a MS ≥ 7.0 earthquake in this region.The probability of earthquake occurrence has significantly increased since the Go

关 键 词：MORLET小波 青藏高原东北缘 岷县漳县6 6级地震 强震活动趋势 

分 类 号：P315.5[天文地球—地震学]