Microwave radiation anomaly of Wenchuan earthquake and its mechanism

Some authors reported that there were anomalies appearing in the satellite remote sensing information before earthquake, including thermal infrared anomaly, water vapor anomaly and microwave anomaly etc. But how to obtain the actual anomaly from the complicated remote sensing information is very difficult due to the influencing of many factors, such as terrain, physiognomy, geological condition, and weather etc. Meanwhile the explaining of anomaly mechanism is another difficultly. In this paper, a new method is proposed to extract the microwave radiation anomaly before Wenchuan earthquake from the AMER-E satellite remote sensing data. The method can eliminate the influencing of terrain, physiognomy and weather. The result of anomaly analysis shows that there was microwave anomaly before and after the main shock of Wenchuan earthquake. In order to explore the anomaly mechanism a physical simulation experiment was carried out. The experimental result shows that the microwave brightness temperature increases in the elastic stage, decreases in the plastic stage, and increases again in the fracturing stage. Based on the experimental result the anomaly mechanism is discussed.