青藏高原东北缘2次地震热红外亮温异常分析

应用静止气象卫星FY-2G的TBB产品为基础数据,针对2017年9月30日四川青川5.4级和2017年10月31日甘肃临潭4.3级地震前后出现在震中区附近的显著热红外异常,运用小波变换和相对功率谱法进行异常提取和资料分析。结果表明:青川地震热红外异常范围主要分布在震中东南区域,震前4个月左右出现功率谱增强现象,持续2个月左右。临潭地震热红外异常范围主要分布在震中的西南方向,震前20 d左右出现异常增强现象,随时间推移,异常范围逐渐向西南扩大,震前14 d异常开始收缩并减弱,异常持续30 d左右。通过对比2次震例,发现热异常特征有许多共同点,其中相同的特征周期可为中强地震前兆特征的归纳提供重要参考信息。

Thermal Infrared Brightness Temperature Anomalies of TwoEarthquakes on the Northeastern Margin ofthe Qinghai-Tibet Plateau

To investigate the markedly thermal infrared anomalies in epicentral areas before and after the Qingchuan, Sichuan M_S5.4 earthquake on September 30, 2017 and the Lintan, Gansu M_S4.3 earthquake on October 31, 2017, in this study, we collected TBB data from China''s geostationary meteorological satellite FY-2G and analyzed the data and spectra using the wavelet- and relative-power-spectrum transform methods. The results show that the thermal infrared anomaly range of the Qingchuan earthquake is mainly distributed in the southeast of the epicenter, and that power spectrum enhancement occurs about four months prior to the earthquake and lasts for about two months. The thermal infrared anomalies of the Lintan earthquake are mainly distributed southwest of the epicenter, with an anomalous enhancement phenomenon occurring about 20 days prior to the earthquake. With the passage of time, this anomaly range expands further southwest. These anomalies begin to shrink and weaken 14 days before the earthquake, and last for about 30 days. A comparison of the two earthquakes shows that there are many common characteristics in their thermal anomalies, which can provide significant reference information for determining the seismic precursor characteristics of moderate-strong earthquakes.