Through the analysis of data of AETA (a system of earthquake precursory signals), before and after Jiuzhaigou Ms 7.0 earthquake in Sichuan Province on August 8, 2017, the result shows that there were 13 AETA stations which captured the associated abnormalities of 36 AETA stations stalled in Sichuan Province, and 9 of which were close related. A typical wave (SRSS wave) of electronic-magnetic disturbance average value found in 11 stations of the 13 stations, had a feature of changing synchronously with the time of sunrise and sunset. An abnormal stripe was found before and after Jiuzhaigou earthquake by PCAETA algorithm applied in SRSS of the 11 stations. Furthermore, the abnormal stripe is also found in Mianning Disaster Prevention and Mitigation Bureau station during August 12 to November 20, in 2017. It is concluded that AETA system can capture close related precursory abnormalities at multiple stations before earthquake and the abnormal stripe of SRSS wave is an obvious and specific earthquake precursory characteristics.

According to the multi-component seismic monitoring system’s technology requirements, an inductive magnetic sensor is presented and the design analysis and industrial implement are discussed. According to the requirements of electromagnetic disturbance monitoring, the authors define the design parameters and propose a well-considered plan on materials choosing and architecture designing. The covered frequency range is 0.1 Hz – 10 kHz, the temperature range is ?40 – 130°C, the monitoring range of magnetic field strength is 1 – 1000 nT, and the sensitivity requirement is larger than 20 mV/nT@(0.1 Hz – 10 kHz). The final test shows that the performance is achieved. This sensor is applied in multi-component seismic monitoring system which is being installed widely.

The authors introduce the multi-component seismic monitoring system AETA (acoustic & electromagnetic testing all in one system). The results of experiments in Yunnan, Sichuan, Tibet, Hebei, Beijing and Guangdong prove that the system AETA has the proper sensitivity with low cost and is easy to be installed. Meanwhile, the raw data and feature data refined from raw data have a good indication of earthquake. More subsequent experiments will be organized in west of China, capital circle of China and Taiwan Strait for deep research on effect of prediction.