Study On The Reliability Of Seismic Signal Recorded By The GPhone Gravimeters

GPhone gravimeter can record digital seismic signals.Some scholars have already noted this situation,but very few research on it has been done.The principal and spectral characteristics of gPhone gravimeter on recording seismic waves share similarities and differences with seismograph,which we typically use to record seismic waves.In order to provide new information sources or method to study the mechanism of the seismic sources,I studied the spectral characteristics and reliabilities of the seismic waves recorded by gPhone gravimeter and compare it with those recorded by CTS-1 seismograph.The main content of the work and results are as follows:1?This paper introduces the system components and observation theory of gPhone gravimeter and CTS-1 seismograph.After examining the physical nature of the two kinds of signals recorded respectively by the two instruments,I conclude that the signals recorded by the instruments in the same station are homologous ground motion.2?This paper analyzes the composition of signals recorded by gPhone gravimeter and CTS-1 seismograph and studies the pretreatment processes to extract the seismic waves.In Lushan earthquake case,I calculate the travel time and epicenter to fit,and find that a few recording time of the signals recorded by gPhone gravimeters are inaccurate,so it is necessary to calibrate the time through fitting results of the seismograph.I get the pretreated seismic waves of the two instruments of every station,and the comparison shows that two waveforms agree well.3?By fitting the maximum amplitude of seismic waves and the epicenter of the gPhone gravimeter and CTS-1 seismograph,the results show that the fitting results are mainly the same.The maximum amplitude decay gradually with the increase of distance in almost all the stations,except for the records from Wenzhou station,which are significantly higher.4?I have calculated the seismic signal amplitude spectrum,power spectrum and the time-frequency spectrum for the seismic(an hour after the earthquake waves and one minute after the P wave arrival time).The comparisons and analysis show that: The correlation of the seismic wave about the two instruments in 12 stations is over 80%,and the signal frequency band of the gPhone gravity meter is not more than 0.5Hz because of the sampling rate;According to the amplitude spectrum and power spectrum,the dominant frequency band of the seismic P wave recorded by the seismograph is less than 0.5Hz,which basically agrees with the gPhone gravity meter.It means that the P wave signal recorded by the gPhone gravity meter can also reflect the seismic source rupture process.With the increase of the distance of the epicenter,the high frequency component of the seismic wave P decay obviously,and the P wave recorded by the two instruments agree better,which indicated that the gPhone gravity meter can accurately record the same seismic response signal of the seismic wave.