首都圈地区中强地震前固体潮调制比特征分析

基于中国全国小震目录，采用固体潮调制比时空扫描方法，对首都圈地区1987年以来的中强地震前固体潮调制比的时空变化特征进行分析。结果表明，对于9次M_S≥5.0地震，有7次在震前1 a、震中100 km范围内出现调制比高值异常，地震对应率为78%；高值异常持续时间通常为3~5个月，并多在震前数月内消失。固体潮调制比分析在首都圈地区表现出较好的映震能力，能为该区域中强地震预测提供一定的参考依据。

The Characteristics of Earth Tide Modulation Ratio before Moderate-Strong Earthquakes in the Capital Circle Area of China

Based on the catalogue of small earthquakes in China, using the temporal and spatial scanning method of earth tide modulation ratio, we analyze the temporal and spatial variation characteristics of earth tide modulation ratio before moderate-strong earthquakes in the capital circle area of China since 1987. The results show that seven of the nine earthquakes (M_S≥5.0) present abnormal modulation ratios, which occurred within 1 a before the main shock and within 100 km from the epicenter. The seismic correspondence ratio is 78%. The abnormal high value intensity usually lasts about 3~5 months. Most disappear in the months before the earthquakes. The analysis of the earth tide modulation ratio shows a good earthquake reflecting ability, and it offers a useful reference for the prediction of moderate-strong earthquakes in the capital circle area of China.