地壳形变短临异常与地下水位短临异常关系及识别方法的初步研究

Preliminary Study on Relation of Short-term and Impending-earthquake Anomalies between Groundwater Level and Crustal Deformation and the Identification Method of Anomalies

对1976以来华北地区MS≥5.0地震前的地壳形变和地下水位资料进行了系统整理,分析研究了地壳形变短临异常与地下水位短临异常间的关系。假如把相距不超过70 km的一组形变与水位异常称为一个异常对次,则有:①临震异常对次远远小于短期异常对次;无论是短期异常还是临震异常,形变异常开始时间大部分早于水位异常开始时间;②在短期异常过程中,变形压或压缩与水位升、变形张或膨胀与水位升的异常对次所占比例不高;变形压或压缩与水位降、变形张或膨胀与水位降的异常对次所占比例较高,且变形张或膨胀与水位降占优。在临震异常过程中,变形压或压缩与水位升的异常对次所占比例远远大于变形张或膨胀与水位升的;③地壳形变短临异常与地下水位短临异常的关系可表示为y=a0x+a1,其中y和x分别为地下水位和地壳形变短临异常观测值。最后提出了判断短临前兆异常的新方法,即异常放大法。

Through analyzing the crustal deformation and groundwater level data in North China betore Ms ≥5.0 earth- quakes since 1976, we study the relation of short-term and impending-earthquake anomalies between crustal deformation and groundwater level. If we regard the deformation and water level anomalies that appear less than 70 km apart early or later as a pair of anomalies, the result shows ： （ 1 ） The number of impending-earthquake anomaly pairs is far less than that of short-term anomaly pairs; most deformation anomalies appear earlier than ground- water level anomalies. （2） During the periods of short-term anomalies, the compressive-deformation and water- level-rising anomalies as well as expansion-deformation and water-level-rising anomalies take a low proportion of the total anomalies, however, the compressive-deformation and water-level-dropping anomalies and expansion- deformation and water-level-dropping anomalies take a high proportion relatively, and expansion-deformation and water-level-dropping anomaly pairs are more of them. In the impending-earthquake anomaly periods, the proportion of compressive-deformation and water-level-rising anomalies is far more than that of expansion-deformation and water-level-rising anomalies. （3） The relation of short-term and impending-earthquake anomalies between crustal deformation and groundwater level is y = a0x ＋ a1, where y and x are the observed values of groundwater level and crustal deformation in short-term and impending-earthquake periods respectively, a0 is the coefficient and a0 is the constant. Meanwhile, we put forward a new method identifying short-term and impending-earth- quake anomaly-Anomaly amplification method.