Thermal infrared anomalies associated with multi-year earthquakes in the Tibet region based on China’s FY-2E satellite data

Using the brightness temperature (TBB) and outgoing long-wave radiation (OLR) data from the FY-2E meteorological satellite, the thermal infrared anomalous change of 20 moderate–strong earthquakes in Tibet from January 12, 2010, to April 30, 2015, are studied. The study calculates the wavelet spectrum change of TBB and OLR based on the Morlet wave and discusses the regulation and characteristics of the anomalous change before and after the earthquakes. The results show that TBB anomalies appeared in 17 of the 20 MS ⩾ 5.0 earthquakes. Anomalies of long-wave radiation occurred in 16 earthquakes. Moreover, their durations, locations and amplitudes are similar. The duration from appearance to disappearance of each anomaly is 30–40 days, the abnormal area is mainly distributed along the faults near the epicentre, and the anomalous maximum amplitude of TBB and OLR’s relative energy spectrum are both times the average. The depths of the moderate–strong earthquakes in the study area are mainly distributed within the upper 20 km, which suggests that thermal infrared can represent the radiation characteristics of shallow earthquakes better. Finally, thermal infrared anomalies of two major earthquakes – the Yushu MS7.1 Earthquake and the Nepal MS8.1 Earthquake are calculated, and both show thermal infrared anomalies. There are few studies on the thermal infrared anomalies of multi-year earthquakes in the Tibet region that use the FY-2E satellite. This study discovers some characteristics of thermal infrared radiation associated with earthquakes in Tibet and looks at the relationship between thermal anomalies and faults. Studying and summarizing thermal infrared anomaly patterns associated with moderate–strong earthquakes in Tibet provide important reference values and can significantly aid earthquake research in this region.