Anomalies of Precursory Group and Grouped Strong Earthquakes in the Sichuan-Yunnan Region

Anomalies of Precursory Group and Grouped Strong Earthquakes in the Sichuan-Yunnan Region

Shi Shaoxian;Cheng Wanzheng

【期刊名称】《中国地震研究（英文版）》 【年(卷),期】2004(018)004

【摘要】Three methods of extracting the information of anomalies of a precursory group are put forward, i.e., the mathematical analyses of the synthetic information of earthquake precursors (S), the inhomogeneous degree of precursory groups ( ID ) and the values of short-term and impending anomaly in near-source area (NS). Using these methods, we calculate the observational data of deformation, underground fluid and hydrochemical constituents obtained from different seismic stations in the Sichuan-Yunnan region and conclude that the synthetic precursory anomalies of a single strong earthquake with Ms6.0 differ greatly from those of the grouped strong earthquakes, for the anomalous information of precursory groups are more abundant. The three methods of extracting the synthetic precursory anomaly and the related numerical results can be applied into the practice of prediction to the grouped

strong

earthquakes

in

the

Sichuan-Yunnan

region.

Inhomogeneous degree (ID) of synthetic precursory anomaly can be identified automatically because it takes the threshold of distributive characteristics of the anomalies of precursory group as its criterion for