Development characteristics and dynamic mechanisms of tectonic ground fissures in Weihe Basin, China

The Weihe Basin is part of the regionally extensive Fenwei Graben System, which is a major tectonic block impacted by active tectonics and human activities. There are 200 tectonic ground fissures in the Weihe Basin, some of which have resulted in loss of life and severe damage to infrastructure. The development characteristics and dynamic mechanisms of these fissures were investigated by surveying, mapping, and geological drilling. The fissures are distributed along the boundary faults between fault blocks with prominent regional, zoning, and directional characteristics. On the profiles of fissures, the tectonic ground fissures are connected with underlying faults and possess the characteristics of synsedimentary faults. The deeper the stratum is, the greater the fault displacement of the stratum is, and the greater the thickness of the strata on the hanging walls is than that on the heading walls. These fissures are driven by dynamic tectonic processes, including uplift of the upper mantle and extension of the crust, differential movement of the fault blocks, and fault activity. The extension and opening of fissures are accelerated by hydrodynamic progresses, including pumping and raining. This paper describes a study of the mechanisms of the fissures and provides guidance for prevention of disasters and reduction of disaster severity in this area.