Anisotropy Features of Earth Tide Response for the First RZB-3 Type Deep-Well Strain Meter in China

The drilling strain observation technique has played a very important role in geodynamics and earthquake prediction, and has been widely used. The first RZB-3 type deep-well strain apparatus was installed at BaiShan station of ChangPing in 2008 by Earthquake Administration of Beijing Municipality. We have achieved a number of observational data of earth tide from the station without influence and interference from ground. The apparatus could record clear and stable earth tide and strain wave with coseism. These data are of good quality and significance. Through the earth tide model of Nakai, we calculated and gained earth tide proportion factors in the directions of deep-well, and verified that the tide response compared to the theoretical model in BaiShan station has a very large dispersion and a regular azimuthal anisotropy from the view of deep-well strain observation. The deep-well earth tide observation with high precision and tidal response anisotropy phenomenon are expected to be applied in the dynamics, earthquake prediction and Geological study, to provide a reference to improve the tide displacements by space geodetic observational data.