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

这项研究是为了提供一个联合的美国组成部分， 美国/中国项目监测北京-天津- 中国唐山-张家口（BTTZ）地区。 引力可以 对导致密度变化的构造变形敏感， 一个站的高程变化，但地下水的影响 高程变化必须在测站无法 位于低孔隙度的结晶岩上。 后者都没有 在BTTZ区域内提供站点类型。 因此 这项研究的一部分是分离地下水， 变化，并研究它们与地震的关系， 可能是地震前兆信息的重要来源， 自己 这项研究是对国家的贡献 减少地震灾害计划。

This research is to provide the U.S. component of a joint US/PRC project to monitor gravity changes in the Beijing-Tianjin- Tangshan-Zhangjiakon (BTTZ) region of China. Gravity can be sensitive to tectonic distortion that causes density changes and elevation changes at a station, but effects of ground water elevation changes must be accounted for where stations cannot be situated on low-porosity crystalline rock. None of the latter station types are available in the BTTZ region. Therefore, a component of this research is to separate the ground-water variations and to investigate their relation to earthquakes which may be an important source of earthquake precursor information in themselves. This research is a contribution to the National Earthquake Hazard Reduction Program.