Study On Earthquake Intensity Rapid Report System In Wuhan City Circle

Earthquake early warning(EEW) can provide seconds to tens of seconds of warning time in the destructive seismic first arrival wave before the arrival. The warning time can take appropriate emergency measures. Intensity rapid report(IRR) can draw the intensity map of the affected region in the destructive earthquake occurs after a few minutes, rapid assessment of casualties and economic losses, and can offer the decision basis for emergency rescue and repair works. These two techniques can help reduce losses after the earthquake, reducing secondary disasters and casualties. The paper focuses on the working principle of earthquake early warning and intensity rapid report, and summarizes the realize methods of earthquake early warning, analyze their advantages and disadvantages and applicable scope, choose reasonable seismic magnitude determination and seismic phase detection method. Analyzing and contrasting the correspondence relationship and statistical methods between the ground motion parameters and intensity, we choose a calculating method of instrumental intensity by triaxial acceleration recorder.Compared with traditional instruments, the intensity meter based on MEMS technology has many advantages such as smaller size, relatively low cost, digital signal output, low-frequency signal observation and so on. A variety of intensity meters based on MEMS sensor have been developed at home and abroad. These instruments are all complex in structure and high in manufacturing cost. With a vast territory, China needs to set up large quantities of the seismic intensity meters. Apparently, the economics cost is too high with the above instruments to monitor seismic intensity in a large area. Therefore, it is necessary to develop a seismic intensity meter of low cost and stable performance to meet the needs of dense layout in a large area, earthquake early warning, rapid intensity report,3D earthquake observation and so on.The seismic intensity meter mainly consists of sensor module, data acquisition module, main control module and data processing module. The meter collects data from three axis MEMS accelerator with200Hz sampling frequency by embedded processor. The value of axis acceleration will be decided whether it exceeds the threshold after the datum been denoised and filtered. If the acceleration value is larger than the threshold, the meter will send the alarming messages to the data center. In addition, the meter can send the instrument intensity value, GPS coordinates, time and the possible instrument failure messages to the data center in real-time. If we collect the data from some meters, we can draw the intensity distribution map and obtain some relevant information according to the provided time, position and intensity information. According to the characteristics of seismic signals, the cutoff frequency of FIR low-pass filter is set to15Hz and the sampling frequency is set to200Hz in this paper.32order Hanning window is used to intercept. Using FDATool the filer coefficients are normalized and quantized to16bit numerical symbols. Using the Sichuan Lushan earthquake data, we conduct the anti-interference and reliability verification of the digital filter, the results meet the design requirements. This paper uses the ARM processor STM32F107as control core, LIS344ALH chip as the sensing element, with24 bit sigma-delta anlog to digital converter ADS1248, the analog signal of the three-axis MEMS sensor is digitized.Finally, this paper propose the idea of the earthquake early warning and intensity rapid report system on Wuhan city circle, the structure is divided into datacenter, backbone network and sub network, according to the various parts of the implementation requirements, making the network mode and the system function. Planning of the earthquake early warning and intensity rapid reference station, basic station and field mobile station.