Analysis of Present Tectonic Stress and Regional Ground Fissure Formation Mechanism of the Weihe Basin

In this paper, the crustal horizontal velocity fields of the Weihe Basin and the Xi'an area are determined using high-precision GPS campaign measurements, which in turn provide constraints to calculate tectonic stress fields. A finite element dynamic model is employed for the Weihe Basin and an elastic block model for the Xi'an area. It is suggested that the ground fissures in the Weihe Basin are shaped by active faults under the effect of a NW-SE regional tension stress field. Fault motion is the fundamental factor influencing the ground fissures and controls their directions and distribution, though the excessive extraction of underground water might be another major factor that accelerates the development of ground fissures. It is believed the results obtained in this study can provide important information for the prevention of basin ground fissure disasters and aid urban construction.