CALIBRATION OF QUARTZ HORIZONTAL PENDULUM TYPE TILTMETER

After briefly mentioning the principle of the quartz horizontal pendulum type tilt-meter, a method for determining the scale value C of such tiltmeters by means of a bearing plate and a flask of mercury is described. Tests show that under different cavity pressures and external loads, the characteristics of the bearing plates are linear and uniform. Two tiltmeters have been tested for different oscillation periods of the pendulum, and 11 determinations have been made for each tiltmeter. The characteristic constants of the scale values, k=CT², are respectively K=6.158±0.031 and k=5.964±0.032. Test observations for a long time a, t the seismic station of Tai-An, Shandong Province show that earth tide can be normally recorded. The drift of the tiltmeter as obtained by taking the daily average of tiltmeter readings over one year is about 1″.