Analysis Of Thermal-Infrared Abnormity Base On Multi-source Remote Sensing Data Before Earthquake

Thermal anomaly occurres before the earthquake,which has long been of concern at home and abroad. With the development of satellite remote sensing technology, it is likely to use thermal infrared remote sensing to detect the Earth's surface temperature distribution and capture the possible thermal anomalies before earthquakes by analyzing satellite data to obtain global surface information in a short time. This paper first summarizes the research status at home and abroad; Next it introduces the physical basis of the earthquake thermal infrared remote sensing and sorts out the relevant mechanism explanations; Then, on the basis of previous research, comprehensively using NCEP-FNL assimilation data, NOAA satellite OLR products and the temperature data from the weather station on the ground, it mainly analyzes three remote sensing thermal anomalies before the earthquake and gets some meaningful conclusions; Finally, it explores the regular characteristics of seismic remote sensing thermal anomalies, and discusses the direction of the future work.The main research content and results of this paper are summarized as follows:1. Using the temperature data of NCEP-FNL material, the paper analyzes the time and space evolution characteristics of the temperature anomaly before the Hualian earthquake in Taiwan in 2010. The results show that the fifth day before the earthquake, in the northwest of the epicenter (ie, the front-end of the plate movement) appeared warming phenomena, and then the temperature anomaly gradually moved to the epicenter, and the temperature anomaly area of the tectonic zone extended to the maximum; Then the anomalies stayed in the area between Okinawa Trough and Ryukyu Trench. They disappeared 2 days before the earthquake.2. Using NOAA satellite OLR data, the paper analyzes the OLR timing changes and its space evolution characteristics before the 2008 Yutian earthquake in Xinjing. The results show that the abnormal temperature increase before the earthquake had the process of starting—enhancing—peaking—damping—quieting—then earthquake again and the earthquake did not occur at the peak of the long-wave radiation anomaly, but occurred a month after the long-wave radiation anomaly quieting. The analysis results are the same as those from the NCEP-FNL temperature data.3. Using NOAA satellite OLR data, the paper analyzes the OLR time series changes and its spatial evolution characteristics before the 2007 Pu'er earthquake in Yunnan. The results show that the OLR sequence before Pu'er earthquake had obvious anomaly precursor with the process of starting—damping—strengthening—peaking—quieting—strengthening—re-earthquake and thermal anomaly area moved gradually along the fault zone to the area near the epicenter. It is consistent with the temperature changes from the weather station on the ground near the epicenter.4. The paper comparatively analyzes the common features and differences of thermal anomaly before the three earthquakes, and explores the laws of thermal anomalies before earthquakes. The results show that using the NCEP-FNL temperature data and long-wave radiation data the thermal anomaly information relative to the tectonic activity and earthquake can be effectively extracted; Generally the thermal anomaly occurres within about 40 days before the earthquake and the anomaly presents the process of beginning—damping—strengthening—peaking—quieting—strengthening—re-earthquake. The spatial distribution of the thermal anomaly area is relevant to the structure of the region. Mostly the anomaly has the gradual process of moving along the fault zone to the epicenter, with a good effects of reflecting earthquake.