西北地区中强震前固体潮调制比时空特征分析

摘要

Based on the shallow-focus earthquakes lunar catalog in Chinese mainland from 1900 to 2015,modulated lunar date and threshold of modulation ratio are defined respectively according to seismic active characteristics.The modulation ratio method is employed to carry out spatio-temporal scanning for three moderate earthquakes in northwest China,and the spatio-temporal characteristics of modulation ratio of regional small earthquakes are analyzed.Results indicate that there are modulation ratio anomalies around epicentral area before Minxian-Zhangxian Ms6.6 earthquake and Alxa Ms5.8 earthquake,evolution time of modulation ratio anomaly is relatively long for Menyuan Ms6.4 earthquake.All three moderate earthquakes happened around the area with higher earth tide modulation ratio according to the spatio-temporal scanning results,and the length of time window and the abnormal area size of the earth tide modulation ratio may have correlations with the magnitude of moderate earthquakes.%基于1900-2015年中国大陆地区浅源地震阴历目录,依据地震活跃特征确定固体潮调制阴历日期和调制比阈值,并利用固体潮调制比时空扫描方法回顾性地研究近年来西北地区发生的3次中强地震,即2013年甘肃岷县漳县Ms6.6、2015年内蒙古阿拉善Ms5.8和2016年青海门源Ms6.4地震前,区域小震的固体潮调制比时空演化过程.研究结果显示:岷县漳县Ms6.6和阿拉善Ms5.8地震前震中区域出现固体潮调制比异常,门源Ms6.4地震前震中附近的固体潮调制比异常演化时间较长;西北地区3次中强震均发生在固体潮调制比时空扫描的高值异常集中地区及周围区域,扫描时间窗长度和固体潮调制比异常区域的大小可能与中强震的强度有一定的相关性.