基于地磁异常分析大别造山带东段构造特征

摘要

以横跨东大别造山带东段的地磁总强度剖面数据和皖中西部地磁总强度加密点阵数据为基础,经过日变通化改正化极、局部与区域异常场的分离,基于分离出的区域磁异常场,使用近似线性反演公式,计算出剖面的居里面平均埋深24 km,最大起伏6 km.通过近30 a的震源深度分析得知,研究区地震震源深度集中分布在1～30 km,表明该区的“发震层”层位与“磁性层”层位正好吻合.结合区域地质、构造演化等资料,揭示了磁性构造特征与孕震的关系.%We use geomagnetic omnidirectional intensity profile data across the east Dabie orogenic belt as a foundation.After a series of processing steps,including diurnal reduction,standard reduction to pole,and extraction of the local anomalous field from regional field,we obtain the regional anomalous field.Based on the regional anomalous field,we use the approximate linear inversion method to calculate the average buried depth of Curie interface along the profile,which is 24 km with a maximum 6 km fluctuation.It is found that the depth of the hypocenter in the last 30 years presents dominance distribution between 1 km and 30 km in the study area and its vicinity.The foregoing data shows that the'earthquake layer'coheres well with the 'magnetic layer'.Combining geologic background with geotectonic evolution,we obtain the seismic precursor relationship with geomagnetic structural features.