重力仪与宽频带地震仪地震波信号分析及其在异常判定中的应用

以2011年3月11日日本东北M_S9.0地震和2013年11月23日3个典型地震(近震、 远震、 深远震)为例， 对泰安地震台JCZ-1甚宽频数字地震仪及LaCoste-PET重力仪的地震波信号进行频谱分析. 结果表明， 由于两套仪器的设计频率响应范围各有侧重， 其对地震波信号的采集能力也有所差别， 信号频谱分布也有所不同, 即地震仪卓越周期较重力仪偏小， 谱能量向高频方向集中， 而重力仪的频谱分布平坦且较地震仪响应周期大. 地震仪和重力仪对长周期地震波信号的响应仍有对应性和可比性， 对1 s以上的地震波信号均有响应， 对远震波形记录有较好的一致性. 宽频带地震仪和重力仪对地震波响应的特性， 为重力观测中阶变突跳等异常变化性质的判定提供了物理学指标， 对形变观测中可能出现的地震前兆异常的认识及判定具有重要意义. 

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.