Earthquakes are reported to be preceded by anomalous increases in satellite-recorded thermal emissions, but published results are often contradicting and/or limited to short periods and areas around the earthquake. We apply a methodology that allows to detect subtle, localized spatio-temporal fluctuations in hyper-temporal, geostationary-based land surface temperature (LST) data. We study 10 areas worldwide, covering 20 large (Mw > 5.5) and shallow (<35 km) land-based earthquakes. We compare years and locations with and without earthquake, and we statistically evaluate our findings with respect to distance from epicentra and temporal coincidence with earthquakes. We detect anomalies throughout the duration of all datasets, at various distances from the earthquake, and in years with and without earthquake alike. We find no distinct repeated patterns in the case of earthquakes that happen in the same region in different years. We conclude that earthquakes do not have a significant effect on detected LST anomalies.

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Time series analysis of land surface temperatures in 20 earthquake cases worldwide

Previous studies have shown that thermal infrared radiation (TIR) changes with stress for loaded rocks. TIR changes were mainly attributed to temperature change without considering the change in surface emissivity. And it remains unclear whether there was a change in emissivity during the rock loading process. Therefore, based on the spectral radiance observations in this paper, an experimental study involving the emissivity variation in the 8.0–13.0 μm range for elastic loaded quartz sandstone under outdoor conditions was conducted. The experiments yield the following results. First, a variation in the stress condition led to the emissivity change in addition to the temperature change. The spectral radiance change was the combined result of the temperature changes and emissivity changes. Second, the emissivity changes linearly with the stress change, and the amplitude is relatively large in the 8.0–10.0 μm range. The waveband features of emissivity variation are the main factor leading to the waveband features of stress-induced radiance change. Third, the explanations for the changes in temperature and emissivity during loading process are analyzed. And the significance and difficulty for further satellite remote sensing purpose is discussed. The experimental results provide an experimental foundation for crustal stress field monitoring.

Experimental Study of the Thermal Infrared Emissivity Variation of Loaded Rock and Its Significance

Experimental investigation on infrared radiation features of fracturing process in jointed rock under concentrated load

Taking the 2017 Mw6.5 Jiuzhaigou earthquake as a case study, ionospheric disturbances (i.e., total electron content and TEC) and thermal infrared (TIR) anomalies were simultaneously investigated. The characteristics of the temperature of brightness blackbody (TBB), medium-wave infrared brightness (MIB), and outgoing longwave radiation (OLR) were extracted and compared with the characteristics of ionospheric TEC. We observed different relationships among the three types of TIR radiation according to seismic or aseismic conditions. A wide range of positive TEC anomalies occurred southern to the epicenter. The area to the south of the Huarong mountain fracture, which contained the maximum TEC anomaly amplitudes, overlapped one of the regions with notable TIR anomalies. We observed three stages of increasing TIR radiation, with ionospheric TEC anomalies appearing after each stage, for the first time. There was also high spatial correspondence between both TIR and TEC anomalies and the regional geological structure. Together with the time series data, these results suggest that TEC anomaly genesis might be related to increasing TIR.

Thermal Infrared and Ionospheric Anomalies of the 2017 Mw6.5 Jiuzhaigou Earthquake

Spatially variable model for extracting TIR anomalies before earthquakes: Application to Chinese Mainland

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

316O Genomic mechanisms of acquired resistance of patients (pts) with BRAF V600E-mutant (mt) metastatic colorectal cancer (mCRC) treated in the BEACON study

. Different temporal and special multi-parameters of infrared remote sensing anomalies of the Yushu earthquake, including the Outgoing Longwave Radiation (OLR), the Land Surface Temperature (LST) and surface temperature from the National Center for Environmental Prediction (NCEP) were studied in this paper. All results confirmed previous observation of thermal anomalies in seismic region prior to this earthquake. Compared to the multi-parameter anomalies, the underground water temperature anomaly appeared first and lasted for the longest time; OLR anomalies reflected the radiation characteristics of the land surface medium as the first infrared parametric anomaly; TBB anomalies appearing later than OLR are abnormal because the results were converted by calculating the radiation value of the underlying surface; the third thermal anomaly was LST. NCEP temperature reflected the average atmosphere temperature with a certain vertical thickness, therefore it was the latest anomaly. The anomalies of OLR, TBB and LST lasted for a similar time length and were nearly located in the south or southwest of the epicenter.

X. D. Zhang

Papers

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

316O Genomic mechanisms of acquired resistance of patients (pts) with BRAF V600E-mutant (mt) metastatic colorectal cancer (mCRC) treated in the BEACON study

Study on multi-parameters of thermal infrared remote sensing anomalies of the Yushu earthquake