Design And Research Of Seismic Infrasound Monitoring Simulation Experimental Device

Earthquakes occur frequently in the 21st century.Earthquake prediction is very urgent because of it's great disastrousness.According to the research data of the earthquake,we know that the infrasound will be issued during the breeding process of earthquake.The harm of the earthquake will be greatly reduced.If the characteristics of the secondary acoustic wave can be analyzed and monitored,it will help people predicting the earthquake time,epicenter and magnitude of the earthquake.In this paper,we take the earthquakes(magnitude greater than or equal to 7)precursor sound waves as the research object and the USGS Geological Survey published in the Earthquake directory as the statistical data source.From 2005 to 2009,there were 62 earthquakes of magnitude 7.0 or above,and all infrasound signals of these were received before the earthquake occurred.In addition,we collected the precursor subsonic waves of Yushu earthquake,Ya'an earthquake,Dingxi earthquake and Yutian earthquake and then studied by the time-domain signals and spectrum.The characteristics of the pre-earthquake sub-acoustic waves are:the infrasound signal can be received within 10 days before seven or more earthquakes.The maximum amplitude of the infrasound signals exceeds 1000mV mostly.The abnormal frequency of it at 10-3Hz and the energy concentrated in the 0.001?0.005Hz from the distribution spectrum of the energy.It is possible for us to distinguish the sub-acoustic waves from the natural infrasound and artificial infrasound through these characteristics.At the same time,the source location theory based on time delay estimation the stereo acoustic sensor array are used to determine the location of the source,and analyze the accuracy of the positioning theory.The key to realize the precise positioning is reasonable placement of the infrasound sensor(position)array.In order to make a better analysis of the earthquake precursor infrasound signal,we proposed and designed a simulation experiment system.Use the 51 single-chip and DAC simulate and produce a number of infrasound signals,and received by high-performance 32-bit microcontroller STM32F103.Then use the FFT algorithm initially analyzes the signal.If the sound pressure level of infrasound signal exceeds the set value,the frequency spectrum was analyzed by FFT firstly,and the signals which does not meet the characteristic of the earthquake preamble was filtered,and the others was used WiFi,GSM/GPRS and other communication means to transmit the data to the cloud server for the further analysis and processing in the cloud server.Finally,determine the three elements of the earthquake.