EARTH TIDES AND SEISMIC WAVES RECORDED BY THE LEVEL FLUCTUATIONS IN A DEEP BOREHOLE AT WALI NEAR BEIJING

The water level in a deep borehole at Wall near Beijing may be used to record the tidal body-strain of the earth. After great earthquakes Rayleigh waves propagate around the earth surface several times and cause the fluctuations of water level in this borehole several times. Its high sensitivity in recording earth tides and seismic waves is believed to be due to the particular hydrogeological conditions.