理塘MS5.1和杂多MS6.2地震热红外亮温异常分析

利用相对功率谱方法对风云卫星热红外亮温数据进行处理, 发现理塘M_S5.1和杂多M_S6.2地震前存在明显的前兆异常。 异常时空演化特征为2016年8月12日在嘉黎—察隅断裂带、 怒江断裂带和澜沧江断裂带开始出现亮温功率谱高值聚集现象, 随后幅值和面积逐渐增大, 持续至9月1日异常面积和幅度达到最大值, 然后逐渐减弱, 2016年9月21日后基本恢复正常, 异常持续近40天。 异常结束后, 分别于9月23日和10月17日在异常区域内发生理塘M_S5.1和杂多M_S6.2地震。 两次地震震中区域平均相对功率谱值时序曲线与异常区域时间演化过程类似, 地震发生在平均相对功率谱值恢复正常背景值之后。

Precursory Anomalies of Thermal Infrared Brightness Temperature before the 2016 Litang MS5.1 and Zaduo MS6.2 Earthquakes

Using relative power spectrum method to deal with thermal infrared brightness temperature data from the Fengyun satellite, we found that there were obvious precursory anomalies before the occurrence of the 2016 Litang M_S5.1 and Zaduo M_S6.2 earthquakes. The characteristic of abnormal temporal and spatial evolution was that high-value aggregation of the brightness temperature power spectrum at the Jiali-Zayu fault, Nu River fault and Lancang River fault on August 12th, 2016. Further, the amplitude and area increased gradually until September 1 reaching its maximum, later gradually decreased and returned to normal on September 21, 2016. The anomaly lasted nearly 40 days. After the occurrence of anomaly, Litang M_S5.1 and Zaduo M_S6.2 earthquakes occurred in the anomaly area on September 23 and October 17 respectively. The average power spectrum time series of the two epicentral region are similar to the temporal evolution of the anomaly region, and the earthquakes occurred after the average relative power spectral values return to normal backgrounds.