庙西凹陷位于渤中坳陷东南部，由北洼、东洼、南洼3 个次级构造单元组成。地震构造解释和断 裂系统分析表明：庙西凹陷北洼和东洼分别由2 个箕状断陷构成，南洼北部为地堑构造，南洼南部为箕状 断陷；各次洼受到郯庐断裂带的影响不同，北洼、东洼受到伸展构造系统的影响，南洼则明显受到郯庐断 裂带的改造。3 个次洼内部的伸展断裂受深层走滑断裂所诱发，构成走滑构造系统的一部分，浅层受张家 口—蓬莱断裂带改造。

Miaoxi Sag is located in the southeast of Bohai Bay, and it is made up by the North subsag, the East subsag and the South subsag. The seismic interpretation and fracture analysis show that the North subsag and East subsag is respectively constituted by two dustpan-shaped fault depression, it is graben structure in the north of South subsag, and dustpan-shaped fault depression in the south. The influences of Tan-Lu fault zone on each subsag are different. The North subsag and East subsag are influenced by extended tectonic system, and the South subsag is influenced by Tan-Lu fault. The extended faults in the three subsags are caused by the strike-slip faults, constituting a part of strike-slip tectonic system, and the shallow faults are transformed by Zhangjiakou-Penglai fault zone.