Comparison of Background Noise of Various Tiltmeters at the Same Site

The normal dynamic state of vertical pendulum, horizontal pendulum and water pipe tiltmeter in Chongli station, as well as the observation data of seismic disturbance, wind disturbance and pressure disturbance are analyzed by the power spectral density method, the results show that: 1) The three kinds of tiltmeters can record the stable background noise relatively clearly. 2) In the corresponding time period, the seismic waves increase the background noise, and the increase of background noise is proportional to the magnitude of the earthquake. With the increase of magnitude, the influence of the frequency range also increase correspondingly. 3) Wind disturbance mainly affects the 0.15~0.3 Hz frequency range, and pressure disturbance mainly affects the low frequency part.