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最近几年,美国在中、南加州以及阿拉斯加地区进行了广泛的地震预报观测研究,其中部分成果(多为阶段成果)刊登在《技术报告总结概要》上。关于地震预报的报告主要包括:前震特征的研究;地形变的连续观测与研究;地下水水位和水质参数的观测和研究以及地应力和重力等的观测研究。以下仅就前三个方面的近期进展情况及初步结果综合介绍如下:一、前震的某些特征按照莫尔纳(P.Molnar)的定义,发生在主震之前、距主震位置100公里以内的地震从广义上称之为前震。如果这种定义是正确的话,可能大部分较大地震(M≥7.0)之前大概
In recent years, the United States conducted extensive earthquake prediction observations in Central and Southern California and Alaska. Some of the results, mostly phase achievements, are summarized in the Summary of Technical Reports. The report on the earthquake prediction mainly includes: the study of the foreshock characteristics; the continuous observation and study of the terrain deformation; the observation and study of the groundwater level and water quality parameters as well as the observation of the earth stress and gravity observation. The following is a brief introduction of the recent progress and preliminary results of the first three aspects as follows: I. Some characteristics of the foreshock According to the definition of P. Molnar, it occurs before the main shock and within 100 kilometers from the main shock location The earthquake is broadly termed as a foreshock. If this definition is correct, probably most of the larger earthquakes (M ≥ 7.0) before about