2001年11月14日昆仑山大地震震前扰动信号的再研究  

A further study of anomalous tremors before the 14 November 2001 Kunlun M_S8.1 earthquake

作　　者：程威 胡小刚[1] 郝晓光[1] CHENG Wei1,2 , HU XiaoGang1,HAO XiaoGuang1(1 State Key Laboratory of Geodesy and Earth＇s Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China; 2 University of Chinese Academy of Sciences, Beijing 100049, Chin)

机构地区：[1]中国科学院测量与地球物理研究所大地测量与地球动力学国家重点实验室,武汉430077 [2]中国科学院大学,北京100049

出　　处：《地球物理学报》2018年第4期1298-1306,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41174022;41321063;41021003;41674100;41374029)资助

摘　　要：研究了2001年11月14日昆仑山MS8.1大地震前新疆地区宽频带地震仪记录到的异常扰动事件.新疆地震台网在发生强震的前三天记录到了强烈的扰动信号.由于新疆地震台距离昆仑山大地震的震中很近,因此该震前扰动的成因备受关注,一直被认为可能是与大地震相关的慢地震事件,可能是大地震的某种前兆现象.本研究扩大了观测异常扰动事件的范围,分析了欧亚大陆187个宽频带地震仪在2001年11月的观测记录,发现这些地震仪在11月10—12日期间都记录到了时频特征类似的强扰动信号,其中最强的扰动信号出现在挪威台站KONO.调查研究发现挪威海域在11月10—12日期间出现了一次超强北极风暴,我们对扰动源位置初步定位后发现大地震前欧亚大陆各台站记录的最大扰动信号主要来源于挪威西南海岸.本文的研究结果确认昆仑山大地震前新疆台网记录到的强烈震前扰动信号不是与大地震相关的慢地震事件,而是挪威海域北极风暴激发的微地震(地脉动).本文进一步研究表明北极风暴激发的地脉动可显著影响中国大陆的地震和重力观测.在分析中国大陆地震台网记录的强扰动信号时,北极风暴的影响不能忽视.Significant anomalous tremors,observed by the Xinjiang Digital Seismograph Network of China before the 14 November 2001 Kunlun MS8.1 earthquake,are further investigated in this study.It is noted that Chinese scientists have paid much attention to these tremors,as they appeared three days before the great earthquake and the stations recorded them are very close to the epicenter.So they were considered a result of an unknown slow-earthquake event,apossible precursor of the great earthquake.In this study,we examined the data of 187 seismographers in Asia and Europe,and found out that all of them recorded significant tremors in November 11—12,2001,three or two days before the main shock.We noted that it is KONO,a station located close to the coast of Norway,recorded the strongest tremor signals.Investigating the historic meteorological reports noticed that a very strong Arctic windstorm occurred in Norwegian Sea in November 11—12,2001.We located an area for generating the significant tremors,which is a shallow sea region close to the southwest coast of Norway.We thus suggest that the significant tremors before the 2011 Kunlun earthquake were not resulted from a slow earthquake event,instead microseismic waves excited by the Arctic windstorm.Our study indicates that the Arctic windstorm can cause significant tremors,which can affect the observations of gravimeters and seismographers in China's Mainland.So micro seismic waves caused by the Arctic windstorms cannot be neglected when we investigate anomalous tremors.

关 键 词：昆仑山大地震 慢地震 地震前兆 微地震 北极风暴 

分 类 号：P315[天文地球—地震学]