基于MODIS数据的伽师—阿图什交界MS5.8地震热红外异常检测研究

Thermal infrared anomaly detection of the MS5.8 earthquake in thejunction area between Jiashi and Atushi based on MODIS data

摘要:

以2011年8月11日在伽师—阿图什交界处发生的5.8 级地震为例,利用MODIS的LST产品数据,采用STL分解法有效地去除地表温度时空数据中的年变趋势及季节因素周期性的影响,对其余的残余项进行GESD异常检测,并分析2008年1月1日至2013年1月1日的LST异常及其他地震的关系数据,研究结果表明:(1)地表温度的变化具有明显的时空变化趋势;利用STL分解法可以看出震前存在明显的热红外异常,增温现象经历了“出现-扩大-分散增温-增温幅度达到极值-消失-发震”等几个阶段。(2)发震前四个月研究区周围存在明显的热红外异常,2月10日发震断层周围出现大面积异常,异常特征持续2个月后的4个月发震,峰值距发震时刻时间间隔较长。(3)余震分布与断裂带和热红外异常分布特征相关,震后大部分余震主要分布在主震发生的震前出现热红外异常的断裂带附近。(4)通过对比同地区相似震例发现,本次地震与 2018年9月4日伽师县MS5.5地震的热异常特征有许多共同点,其中相同的峰值距发震时刻的时间间隔具有一致性,为震前热红外异常特征的归纳提供典型的参考信息。该次地震热红外异常显著,进一步验证了卫星热红外异常在地震预判方面的作用。

Abstract:

An M_S .8 earthquake occurred at the junction area between Jiashi and Atush on August 11, 2011. In this paper, the annual variation trend and the periodic influence of seasonal factors in the spatio-temporal data of surface temperature were effectively removed by using the LST product data of MODIS and STL decomposition method. The GESD test was carried out on the remaining residual terms for anomaly detection, and the LST anomaly and data of other earthquakes from January 1, 2008 to January 1, 2013 were analyzed. The results showed that: (1) The surface temperature has an obvious change trend in time and space; It can be seen that there was an obvious thermal infrared anomaly before the earthquake by using the STL decomposition method, and the temperature increase phenomenon experienced several stages: "appearance-expansion-dispersive temperature increasing-temperature increase to extreme value-disappearance-earthquake occurrence". (2) There were obvious thermal infrared anomalies around the study area four months before the earthquake. Widespread anomalies appeared around the seismologic fault on February 10 and lasted for two months. The earthquake occurred four months later, and there was a long time interval between the peak value and the occurrence time of earthquake. (3) The distribution of aftershocks is related to the fault zone and the distribution characteristics of thermal infrared anomalies. After the earthquake, most of the aftershocks are mainly distributed near the fault zone where thermal infrared anomaly appeared before the main shock. (4) By comparing similar earthquake events in the same area, it is found that the thermal anomaly characteristics of the M_S5.8 earthquake have much in common with the M_S5.5 earthquake in Jiashi County on September 4, 2018. The significant thermal infrared anomalies of the M_S5.8 earthquake further verify the role of satellite thermal infrared anomaly in earthquake prediction.