Experimental study and active tectonics on the Zhangjiakou-Penglai fault zone across North China

Abstract

The Zhangjiakou-Penglai Fault Zone (ZPFZ), as a large-scale WNW-trending active fault zone with frequent seismic activity, is an area prone to moderate to intense earthquakes across North China. A detailed analysis of the ZPFZ has been carried out based on earthquake activity, deep structural response, dynamic mechanism and physical simulation by conducting an en échelon fault model experiment. The results show that the ZPFZ is a lithospheric active fault zone that has controlled some small en échelon Quaternary pull-apart basins and has triggered many earthquakes as seismogenic structures. The earthquake location and intensity distribution by the experimental simulation fit well with those of actual earthquakes. The earthquake distribution is controlled obviously by the en échelon structural properties. The intensity of seismic activity is strong in the middle and weak at the western and eastern ends of the fault zone, migrating from the southeast to the northwest along the entire fault zone. This WNW-trending fault zone in North China, is closely related to the surrounding plate activities. The ZPFZ is not only dominated by the collision of the Indian Plate to the Eurasian Plate, but is also influenced by the subduction of the Pacific Plate. It depends on the comprehensive reflection of two geodynamic settings from the western collision of the Indian to the Eurasian plates and the eastern subduction of the Pacific Ocean Plate to the Eurasian Plate.