Abstract: The contents of Al,Si,Fe,Mn,Zn and La in the hot water show a great amplitude of anomalous and trending variations prior to moderate and small earthquakes occurring along the faults and their adjacent areas,the patterns of which may be controlled by the coseismic stress fields and local geologic structures. However,the time sequence the amplitude of the anomalies related to appearing anomalies may be controlled by the chemical properties of the elements and their partitions. These elements in questions are easy to form parts of the colloid in the hot wateror to be absorbed bv the colloid.which are more sensitive to the medium than other ions andcomplexs,the anomalies in question can be regarded as an indicator of the occurrence of earth-quakes.

Key words: Ground water, Hydrogeochemical survey, Trenc anomaly, Impending earthquake anomaly, Active fault zone

摘要： 通过对北京顺义李遂地下热水井观测研究表明,热水中的Al、Si、Fe、Mn、Zn和La的含量在断裂带及其邻近地区发生的中、小地震前,产生较大幅度的趋势性异常和临震异常变化。其变化形态主要受孕震时区域应力场、观测井所处的地质构造条件控制,异常出现的时间顺序和幅度则取决于元素自身的化学性质和配分。这些元素在热水中易形成胶体或被胶体所吸附,较其它离子或络合物分子对介质有更强的敏感性,可作为地震前兆的灵敏元素。

关键词: 地下水, 水文地球化学测量, 趋势异常, 临震异常, 活动断裂带