华南沿海地震带地震调制比特征分析

1.海南省地震局,海口570203;2.广西壮族自治区地震局,南宁530000;3.广东省地震局,广州510070

中强地震;地震调制比

Characteristics Analysis of Seismic Modulation Ratio of South China Coastal Seismic Zone
ZHANG Hui1,XIE Xiaoling1,YAN Chunheng2,WANG Xiaona3,HUANG Zhangrong1

1.Hainan Earthquake Agency , Haikou 570203, China;2.Earthquake Agency of Guangxi Zhuang Autonomous Region , Nanning 530000, China;3.Guangdong Earthquake Agency , Guangzhou 510070, China

Moderate and strong earthquakes;Seismic modulation ratio

DOI: 10.13512/j.hndz.2022.04.15

备注

利用调制比扫描方法,对1970—2019年华南沿海地震带5级以上中强震进行震前小震调制比全时空特征回溯性研究,分析区域中强地震前调制比时空演化过程。结果显示,调制比高值异常对华南沿海地震带中强震有一定的指示意义:调制比大于0.59且持续2个月则视为异常,高值异常空间尺度大于15000km2,中强震一般发生在异常开始2~15个月或异常消失1~10个月,震中位置大多在异常区域及周边120km范围内的区域,震级与调制比演化时间、空间特征不存在严格的相关性。预测效能评估R=0.50,R0=0.27。通过震例回溯,调制比异常可以作为一种辅助手段,研判未来中强地震发生的时间和位置。
Using the modulation ratio scanning method,this paper conducts a retrospective study on the full time and space characteristics of the modulation ratio of small earthquakes before the moderate-strong earthquakes with M≥5 in the South China coastal seismic zone from 1970 to 2019,and analyzes the temporal and spatial evolution of the modulation ratio before the regional moderate-strong earthquakes. The results show that the abnormal high value of the modulation ratio has a certain indication significance for the moderate and strong earthquakes in the South China coastal seismic zone: When the modulation ratio is greater than 0.59 and lasts for 2 months, it is regarded as an anomaly;the spatial scale of the anomaly with high value is greater than 15 000 km2,and moderate and strong earthquakes generally occur 2-15 months after the anomaly begins or 1-10 months after the anomaly disappears;the epicenter is mostly in the anomaly area and the surrounding area within 120 km;there is no strict correlation between the magnitude and the time and space characteristics of the modulation ratio evolution. The predictive efficacy evaluation R=0.50, R0=0.27. Through the backtracking of earthquake cases, the anomaly of modulation ratio can be used as an auxiliary means to judge the time and location of moderate and strong earthquakes in the future.
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