江苏盐城盐纺井地球化学异常信息提取及机理分析

Geochemical Abnormal Extraction and Mechanism Analysis of the Yanfang Well,Yancheng City,Jiangsu Province

摘要:

依据江苏省盐城市纺织厂井Ca²⁺和Cl^-月均值浓度，利用从属函数和自适应阈值法对该井进行了地球化学异常信息提取与分析；结合波速比和地磁谐波振幅比数据，利用膨胀扩容模式开展了映震机理讨论。结果表明，2008～2016年Ca²⁺浓度出现6次从属函数异常和5次自适应阈值异常，Cl^-浓度出现4次从属函数异常和5次自适应阈值异常，较好地对应了台站200km范围内M_L≥4.0的地震。此外，根据波速比、地磁谐波振幅比和该井地下水地球化学成因等分析结果，判断Ca²⁺、Cl^-浓度在震前的快速上升与深部流体上涌有关。

Abstract:

In this paper,based on the subordinate function method and adaptive threshold method,the Ca²⁺ and Cl^-concentration monthly observation data of Yancheng Yanfang Mill in Jiangsu Province were analyzed and anomalies before earthquakes were extracted. Combined with wave velocity ratio and geomagnetic harmonic amplitude ratio data,the mechanism of reflecting earthquakes was discussed by the dilatancy-diffusion model. The results show that from 2008 to 2016,Ca²⁺ concentration has 6 subordinate function anomalies and 5 adaptive threshold anomalies,Cl^- concentration has 4 subordinate function anomalies and 5 adaptive threshold anomalies,which correspond well to earthquakes of local magnitude above 4.0 within 200km of epicenter distance form the station. In addition,according to the results of wave velocity ratio,geomagnetic harmonic amplitude ratio and geochemical origin of groundwater,it is judged that the rapid rise of Ca²⁺ and Cl^- concentration before earthquakes are related to the upwelling of deep fluid.