麻城1932年6．0级地震区地球物理场与深部环境研究
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摘要
研究了麻城地区重、磁异常场特征，经反演计算获得了深部结构特征。对重力布格异常利用Ｐａｒｋｅｒ－Ｏｌｄｅｎｂｕｒｇ快速位场反演方法计算出莫霍面的展布，对航磁异常利用对数功率谱法和矩谱法计算出居里面深度。在此基础上，探讨该震区深部蕴震条件。主要结论是：①麻城－团凤断裂带为该区切割较深的主要控震构造；②１９３２年麻城６．０级地震发生在区域重力异常等值线梯度最大处，磁力异常区两局部正异常间的低值带，莫霍面及居里面隆起区边缘；③发震部位有其特定的深部蕴震构造及应力蕴震条件。
In this paper,the features of the gravity anomaly and the magnetic anomaly field in Macheng region are exactly investigated,and the deep structural characteristics are obtained by inversion computation.Using the Parker-Oldenburg's formula of rapid inversion of potential field,the Moho depth distribution is computed with the Bouguer sravity anomaly in the region,and using the logarithmic power spectrum method and the moment spectrum method,the Curier isotherm depth is computed with the airborne magnetic anomaly in the region.On this basis,the seismogenic environment in the earthquake area is discussed.The main conclusions are:a)The Macheng-Tuanfeng fault is the essential active fault cutting deeply and controlling earthquake in the region;b)The Macheng(Ms 6.0)earthquake in 1932 occured in the area where the gradient of the regional gravity anomaly is maximum,the lower value zone between two sectional peitive anomalies of the regional magnetic anomaly exists and there is the border of uplift area of both the Moho surface and the Curier isotherm;c)There are specific deep seismogenic tentonic and seismogenic stress condition in the area.
In this paper,the features of the gravity anomaly and the magnetic anomaly field in Macheng region are exactly investigated,and the deep structural characteristics are obtained by inversion computation.Using the Parker-Oldenburg's formula of rapid inversion of potential field,the Moho depth distribution is computed with the Bouguer sravity anomaly in the region,and using the logarithmic power spectrum method and the moment spectrum method,the Curier isotherm depth is computed with the airborne magnetic anomaly in the region.On this basis,the seismogenic environment in the earthquake area is discussed.The main conclusions are:a)The Macheng-Tuanfeng fault is the essential active fault cutting deeply and controlling earthquake in the region;b)The Macheng(Ms 6.0)earthquake in 1932 occured in the area where the gradient of the regional gravity anomaly is maximum,the lower value zone between two sectional peitive anomalies of the regional magnetic anomaly exists and there is the border of uplift area of both the Moho surface and the Curier isotherm;c)There are specific deep seismogenic tentonic and seismogenic stress condition in the area.
引文
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