Analysis of high-frequency signal recorded by gravimeter and broadband seismometer and its application to anomaly identification

Taking the Tohoku, Japan, M_S9.0 earthquake on March 11， 2011， and three typical earthquakes (near earthquake， teleseism， distant deep-focus earthquake) on 23 November 2013， for examples， the coseismic responses of JCZ-1 broadband digital seismometer and LaCoste-PET gravimeter were analyzed by means of frequency spectrum. Since the response range of design frequency for the two types of instruments are different， their signal acquisition capabilities and the signal spectral distribution are different. The predominant periods of seismometer are smaller than that of gravimeter. However， they still show well corresponding and comparability in response to the high-frequency crustal deformation signals. They response synchronously to those high-frequency seismic waves with period more than 1 s， and they have good consistence for teleseism wave recording. The characteristics of synchronous response to high-frequency crustal deformation signals recorded by gravimeter and broadband seismometer provide physics index for those high-frequency anomalies occurred in gravity observation， which is significant to identification of earthquake precursors probably appeared in deformation observation.