VP型垂直摆倾斜仪观测频带的分析及改进

Research and Improvement of the Observation Band of the Vertical Pendulum Tilt Meter

从仪器原理、传递函数和观测数据等方面分析目前在网进行1 Hz采样的VP型垂直摆倾斜仪在2~60 s周期内的频率特性,认为该仪器可以观测到频带内的信号变化,但因处于过渡带,观测幅度较真实幅度削弱约20~40 dB。对VP型垂直摆倾斜仪观测频带进行拓展,使2~60 s周期内的观测信号由之前的过渡带进入到仪器的通频带,结果与相同采样率的其他定点形变仪器的观测效果相同,将地倾斜观测量转换为加速度表达后,其幅频特性符合全球地震背景噪声模型。改进后的VP型垂直摆倾斜仪对于远距离震级不大的同震体波震相记录效果略优于改进前,但受地脉动影响,在识别非地脉动信号时需要采用更精细的方法和手段来提高识别效果。

Research on the instrument principle,transfer function and observation data of the vertical pendulum tilt meter(VPT)in the 2-60 s band shows that the VPT can record the signals in this band.As the band is a transition band,the response of ground motion on the observed data is weakened about 20-40 dB.The VPT’s frequency band is improved in order to expand the signals of the 2-60 s periods in pass-band.The results show the same as other fixed deformation observations with 1 Hz samplings.After transforming the observation into the expression of acceleration,the amplitude-frequency characteristics coincide with global seismic background noise model,which would be a new way to analyze the VPT data.The improved VP vertical pendulum has a slightly better effect on the body phase recording of earthquakes with long distance and medium magnitude than before.However,due to the influence of ground micro-tremor,we need more refined methods to improve the recognition effect in identifying non-ground micro-tremor.