Consistency Analysis of Observation Data from Different Types of Pendulum Tiltmeters

The characteristics of tide factor and component trend of four pendulum tiltmeters (SSQ、VS、RZB and CZB) at Tai'an station are analyzed using Correlation Coefficient method. The influence of pumping water and rainfall on tilt observation data is analyzed by using S-transform and rainfall efficiency, and the degree of influence of air pressure variation interference and the ability of reflecting earthquake are also analyzed. The results show that the pendulum tilt observation has certain consistency in the changing trend, as well as in the influence of pumping water, air pressure and rainfall disturbance, so it can support each other in the data analysis and anomaly recognition. The consistency of observation between SSQ and VS instrument is the highest, however, there are differences in their specific manifestations and the extent of change. The frequency of pumping interference signal is below 0.6×10^-3 Hz, and the NS component is more affected by pumping than the EW component. The closer the instrument is to the well, the closer the depth of the instrument is to the depth of the well, the greater the influence is. The efficiency of continuous rainfall in the initial period of rainy season is greater than that in the second period, and the efficiency of NS component is higher than that of EW component. The SSQ and VS instruments in the cave are more seriously disturbed by air pressure than the RZB and CZB instruments in the borehole. The filtering performance of the deformation instruments itself results in a great difference in the earthquake-reflecting ability of the instruments, and the difference of recorded earthquake numbers can reach nearly 12 times.