2017年九寨沟MS7.0地震前热红外亮温异常与盆地效应

Anomaly of thermal infrared brightness temperature and basin effect before Jiuzhaigou MS7.0 earthquake in 2017

  • 摘要: 以中国静止气象卫星亮温数据为数据基础,采用小波变换和功率谱估计方法进行处理分析,并对处理后的数据进行时空扫描。结果表明:① 在2017年8月8日九寨沟MS7.0地震前,沿龙门山断裂带存在一条热红外辐射增温带,其热辐射异常主要分布于四川盆地边缘,异常面积最大可达6×104 km2,九寨沟地震即发生在增温区域的边缘;② 九寨沟地震的相对功率谱时序演化特征显示,2017年7月初相对功率谱幅值迅速升高以后,长时间持续呈高幅值状态,且与过去十年的数据相比相对功率谱较为突出,直到地震后一段时间才恢复;③ 九寨沟地震异常的分布与汶川地震前热辐射异常展布相似,对其它发生在含油气盆地边缘的地震进行综合分析认为,热辐射异常均具有类似盆地形态的特征,反之,这种类似盆地形态的异常与MS≥6.5地震的对应率为75%;④ 地震盆地效应是位于盆地边缘的、具有不同发震构造的地震表现出相似的热辐射空间展布的主要原因,与地球放气理论机理解释相一致。

     

    Abstract: In this paper, wavelet transform and power spectrum estimation methods are used for processing and analyzing the brightness temperature data from China’s geostationary meteoro-logical satellite. Then the obtained time-frequency data is scanned by time and space scanning method. The results show that: ① Before the Jiuzhaigou MS7.0 earthquake on August 8, 2017, there was a thermal infrared radiation warming zone along the Longmenshan fault zone. The thermal radiation anomaly is mainly distributed on the edge of the Sichuan basin, with an anomalous area of 6×104 km2. The Jiuzhaigou earthquake occurred at the edge of the warming area. ② The time series evolution characteristics of relative power spectrum of the Jiuzhaigou earthquake show that after the relative power spectrum amplitude increases rapidly in early July 2017, there is a long-term continuous high amplitude state, which is more prominent than the data of the past ten years. It did not recover until some time after the earthquake. ③ The anomalous distribution of the Jiuzhaigou earthquake is similar to that of the Wenchuan earthquake. The comprehensive analysis of other earthquakes occurring at the edge of the petroliferous basin suggests that the thermal radiation anomalies are similar to the basin morphology. The corresponding rate of this basin-like anomaly is 75% compared with the MS≥6.5 earthquake. ④ The earthquake basin effect is the main reason for the similar thermal radiation spatial distribution of earthquakes with different seismogenic structures located at the edge of the basin, which is consistent with the theoretical explanation of the earth deflation theory.

     

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