湖北及邻区中强震前固体潮调制比特征分析

The Characteristics of Earth Tide Modulation Ratio before Moderate Earthquakes in Hubei Province and Its Adjacent Areas

摘要:

采用固体潮调制比时空扫描方法,对2000—2023年湖北及邻区16次4级以上地震进行回溯性研究,分析中强地震前调制比时空演化特征。当固体潮调制比最大值连续三个月不低于0.8,且异常空间尺度不小于15000km²时可视为异常。结果表明,12次 (75%) 地震前存在调制比高值异常,表明该方法对湖北及邻区中强震有一定的指示意义。中强地震通常发生在调制比高值开始后5～20个月或异常结束后13个月内,优势发震时段为异常持续期间或异常结束后9个月内; 震中位于异常区域及周边150km范围内,其中5级以上地震均发生在异常区域及周边50km范围内; 震级与异常最大值存在一定的关联,5级以上地震前异常显著程度通常较高; 预报效能评估R=0.671,R₀=0.274。固体潮调制比方法可为湖北及邻区中强地震预测提供一定的参考依据。

Abstract:

This study retrospectively analyzes the spatio-temporal evolution characteristics of the Earth tide modulation ratio (R_m) prior to moderate earthquakes in Hubei Province and its surrounding regions,using a spatio-temporal scanning method. A total of 16 earthquakes with magnitudes of 4.0 and above,occurring between 2000 and 2023,were examined. Anomalies are identified when R_m values are equal to or exceed 0.8 for at least three consecutive months,and the spatial extent of the anomalous area surpasses 15,000km². The results indicate that elevated R_m values were observed prior to 12 of the 16 events (75%),suggesting that the R_m method holds predictive significance for moderate seismic activity in the region. Moderate earthquakes typically occurred within 5 to 20 months after the onset of elevated R_m or within 13 months following the termination of the anomaly,with the most favorable predictive window being within 9 months. Epicenters were generally located within anomalous areas or within 150km of them. Notably,all earthquakes with magnitudes above 5.0 occurred within anomalous zones or within 50km of such zones. A positive correlation was observed between earthquake magnitude and the maximum R_m value,with anomalies preceding M≥5.0 events showing higher statistical significance. The method's predictive capability,evaluated using correlation coefficients,yielded R =0.671 and R₀=0.274. These findings suggest that the Earth tide modulation ratio method can serve as a viable tool for forecasting moderate earthquakes in Hubei Province and adjacent areas.