太康MS4.7地震构造初步分析

对比分析石油地震剖面和高分辨浅层地震剖面，依据震源机制解、地震精定位结果，给出太康MS4.7地震区深浅断裂的展布关系。结合区域构造演化认为，晚白垩世至古近纪，太康隆起发生NWW和NE-NNE向张剪性走滑断层活动，其产生的伸展拉张作用使隆起解体，形成目前凸凹相间的构造格局；新近纪以来，在太康隆起整体接受沉积的背景下，构造活动强度有所减弱，但凸凹相间的构造变形样式得以延续，表现为控制断陷的边界断层的持续活动，同时，一系列新近纪-第四纪铲式正断层的形成也表明深部走滑伸展作用的存在；太康MS4.7地震区深部震源构造表现为沿近NW和近NE走向的高角度断层，浅部构造表现为受近NW向铲式张性断层控制的凸凹相间的构造样式，这种深浅构造展布形式共同控制了太康MS4.7地震及其余震的发生。

Preliminary Seismotectonic Analysis of the Taikang MS4.7 Earthquake

Based on comparative analysis of petroleum seismic and high-resolution shallow seismic profiles, combined with the focal mechanism solution and earthquake location results, we establish the shallow-deep faults distribution below the Taikang MS4.7 earthquake zone. Combining regional tectonic evolution from the late Cretaceous to Paleogene, NWW and NE-NNE shear strike slip movement in Taikang uplift makes the uplift break up into alternately tectonic conditions.Since the Neogene,under the background of the whole deposition of the Taikang uplift, tectonic activity has weakened, but tectonic deformation style alternately continues, showing sustained activity of rift boundary fault control.Furthermore, the formation of a series of Neogene Quaternary normal faults indicates the existence of deep strike slip extension.The deep source structure of the Taikang earthquake area is near NW and NE high angle faults, and the shallow structural performance is alternately tectonic style controlled by near NW strike slip faults. The deep and shallow structures controls the occurrence of the Taikang MS4.7 earthquake and its aftershocks.