巴颜喀拉块体中东段M_(S)≥7.0地震卫星红外辐射时间序列变化特征  

Variation features of satellite infrared radiation time series associated with MS≥7.0 earthquakes occurred in the Mid-Eastern Bayan Har block

作　　者：张铁宝[1] 杨星 路茜[1] 龙锋[1] 管勇[1] ZHANG TieBao;YANG Xing;LU Qian;LONG Feng;GUAN Yong(Sichuan Earthquake Agency,Chengdu 610041,China)

机构地区：[1]四川省地震局,成都610041

出　　处：《地球物理学报》2023年第4期1496-1507,共12页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(42074082);国家重点研发计划项目(2019YFC1509205)共同资助。

摘　　要：2008年以来,在中国青藏高原腹地的巴颜喀拉块体中东段接连发生了2008年四川汶川8.0级、2013年四川芦山7.0级、2017年四川九寨沟7.0级以及2021年青海玛多7.4级地震.本文基于MODIS卫星红外数据,利用平滑方法提取了2004年4月—2022年2月(近18年)巴颜喀拉块体中东段的红外亮温均值时间序列低频信息,分析了汶川8.0级、芦山7.0级、九寨沟7.0级以及玛多7.4级地震前后红外辐射低频信息的变化特征.研究结果表明,4次大地震前后红外辐射变化具有以下共性特征:(1)大地震前,巴颜喀拉块体中东段整体辐射值处于增强阶段,地震后,辐射值转为减弱阶段.这与弹性变形阶段岩石应力加载升温、卸载降温过程类似;(2)在4次大地震前的辐射增强阶段,辐射值均出现了大幅度的超2倍标准差辐射增强异常,这对巴颜喀拉块体中东段的7级以上地震具有一定的预警意义.这些共性特征有助于设计一个合适的技术方案来跟踪判断巴颜喀拉块体中东段7级以上大地震的危险性.The M_(S)8.0 Wenchuan earthquake in 2008,the M_(S)7.0 Lushan earthquake in 2013,the M_(S)7.0 Jiuzhaigou earthquake in 2017,and the M_(S)7.4 Madoi earthquake in 2021 have occurred continuously in the Mid-Eastern Bayan Har block,which located in backland of the Qinghai-Tibetan plateau,since 2008.This research makes use of the TIR(Thermal Infrared Radiation)data inverted from the MODIS/Terra Sensor,taking advantage of the smooth method to derive the low-frequency information in the time series of the Brightness Temperature's average value from April 2004 to February 2022(nearly 18 years)in the Mid-Eastern Bayan Har block,analyzing the variation features of the TIR's low-frequency information before and after the M_(S)8.0 Wenchuan,M_(S)7.0 Lushan,M_(S)7.0 Jiuzhaigou,and M_(S)7.4 Madoi earthquakes.The research result shows that the infrared radiation changes before and after the four major earthquakes have the following common features:(1)The whole radiation value of the Mid-Eastern Bayan Har block keeps in the enhancement stage before these earthquakes and turns to the weakening stage after these earthquakes.This phenomenon is similar to the changes in the rock's stress loading and unloading experiment during the elastic stage,which indicates that the loading gives rise to the temperature's rising and the unloading leads to the temperature's decrease.(2)The radiation value all overpast the 2 times standard deviation a lot during the enhancement stage before these four major earthquakes.This anomaly phenomenon is indicative for the M_(S)≥7.0 earthquakes in the Mid-Eastern Bayan Har block.Based on these common features,a suitable technical scheme can be designed to track and judge the risk of large earthquakes in the Mid-Eastern Bayan Har block.

关 键 词：汶川地震 玛多地震 卫星红外辐射 巴颜喀拉块体 MODIS 

分 类 号：P315[天文地球—地震学]