Anomaly extraction capability analysis based on the mean line difference enhancement ratio method for thermal infrared phenomena before the Jishishan M6.2 earthquake in Gansu Province and Noto M7.6 earthquake in Japan

On December 18, 2023, a M6.2 earthquake occurred in Jishishan County of Gansu Province, and on January 1, 2024, a M7.6 earthquake occurred in Noto, Japan, with a short interval between the two earthquakes. They caused a large number of deaths and huge property losses with causing great concern in the seismic community. By using the mean line difference amplitude enhancement ratio method, it was found that there were significant thermal infrared anomalies before the two earthquakes. About 110 to 90 days before the Jishishan earthquake, the activity of long-wave radiant thermal infrared was 1.5 to 5 times higher than the historical average. Thermal infrared activity levels were 3 to 4 times higher than the historical average for about 140 to 100 days before the Noto earthquake in Japan. These results once again prove that there are thermal infrared anomalies before strong earthquakes, and also indicate that the mean line difference amplitude enhancement ratio method has strong ability to extract thermal infrared anomalies.