The U.S./China Joint Research on the Variation of Gravity and the Occurrence of Earthquakes in the BTTZ Region, P.R.C.

This research is to continue gravity monitoring as part of an earthquake hazards program in the Beijing region of China. Gravity is monitored by means of eight Geodynamics TRG-1 tidal gravimeters installed at semi-permanent sites, and at a number of stations visited periodically with three LaCoste-Romberg Model G gravimeters. The monitoring program was begun in 1981 as part of the U.S./PRC Protocol on Earthquake Studies and has continued to the present, thus forming a valuable continuous record exceeding ten years. Gravity is related to elevation changes and subcrustal mass movements that have been proposed to be a part of the process of preparation for earthquakes. This region surrounding Beijing is designated by the PRC earthquake hazard program as one of high probability for the next major earthquake in China. This research is a component of the National Earthquake Hazard Reduction Program and the U.S./PRC Earthquake Studies Protocol.