Back‐arc regions, located in the overriding slabs and separated from fore‐arcs by magmatic extrusion, are closely coupled with subduction zones. The width of back‐arc extension is broadly varied in the world. Although the dynamics of the subducting slab is widely studied, the coupling between subducting slab dynamics and back‐arc extension development is still poorly understood. In this study, we aim to numerically analyse how subducting slab retreat influences back‐arc extension, with particular attention paid on the coupling between subducting slab dynamics and back‐arc extension dynamics. Geometry evolution of the subducting slab in the deep upper mantle is investigated. Furthermore, we investigate key parameters that may control back‐arc extension dynamic pattern and process. We perform systematically a set of numerical experiments with 2D high‐resolution thermo‐mechanical coupled oceanic–continental subduction models.

In recent years, moderate earthquakes with a magnitude of about 5.0 have occurred along the Fuyu/Songyuan-Zhaodong fault frequently. This fault is the most seismic active fault in the Songliao Basin, even in the Northeast Seismic Region of China. Based on previous studies, this fault has obvious segmentation from its activity. Some scholars considered the ground stress changes, which caused by the high pressure water injection method of oil exploration in Chaganhua area, maybe the reasonable interpretation of this phenomenon. This paper tries to synthetically assess and review the activity and segmentation of this fault, combining with previous data and the latest research findings. We also tried to reveal the relationship between the high seismicity and high pressure water injection of oil exploration. This effort will help us to understand the fault active characteristics and preparation tectonic conditions of the moderate earthquake in the weak seismic activity region such as the Songliao Basin or the Northeast Seismic Region of China.