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本文介绍了八十年代以来宁夏几次中强地震前的重力异常资料。识别异常的标志是,以幅值大于2mσ为依据。重力异常形态有正也有负;异常空间展布范围一般局限在距震中60km的区域内,该区出现较强的垂直差异运动,显示异常的重力测段多分布在地震烈度衰减较慢的一侧;异常持续时间约为几个月至一年半,而且近离震中区的重力测段比远离震中区的测段异常出现早,持续时间长。其中有的异常是地震前就有所察觉并据此提过内部试报意见。
This paper introduces the gravity anomalies before the moderate-strong earthquakes in Ningxia since the eighties. Identify abnormal signs is to amplitude greater than 2mσ basis. The anomaly patterns of gravity are positive and negative. The distribution range of anomalous space is generally limited to 60 km away from the epicenter. Strong vertical differential motion occurs in this area, showing that the anomalous gravimetric segments are mostly distributed on the slower side of seismic intensity attenuation ; The anomalous duration was about several months to a year and a half, and the gravitational segments near the epicenter were earlier than the anomalous segments away from the epicentral region for a long time. Some of these anomalies were detected before the earthquake and the internal trial report was submitted accordingly.