Distribution and mechanism of the ground fissures in Wei River Basin, the origin of the Silk Road

Wei River Basin (WRB) is the origin of the ancient and new Silk Road, and it is located in Southern Fen Wei Graben System, China. Since 1950s, hundreds of ground fissures have formed in this affluent basin, and these ground fissures have become the main geohazard in WRB. This paper used a series of geological investigations, such as site investigation, trench excavation, geological drilling and geophysical survey to understand the distribution and mechanism of formation of the ground fissures in WRB. The results are: (1) 212 ground fissures in WRB were located in Xi’an, Xianyang, Weinan city, and they have clear orientations, mainly distributed from NEE to SWW, NW to SE, and E to W. Moreover, the ground fissures are accompanied by active faults along the same directions. (2) Ground fissures in WRB can be divided into two types—some ground fissures display obvious horizontal and vertical separations on the earth surface, whereas others only display obvious horizontal separations on the earth surface. (3) Ground fissures in WRB are triggered by four factors, viz. basin structure, active fault, human activities and loess erosion. (4) The mechanism for the formation of ground fissures has also been proposed: tectonic faulting is the fundamental cause of ground fissures in the Wei River basin, and imbalances in the man-land caused by human actives accelerated the ground fissures activities. (5) Many effective measures have also been proposed to mitigate the hazards of ground fissures in WRB, such as planning, engineering measures, controlling the exploitation of groundwater and monitoring. This research will be helpful in safeguarding the sustainable development of the Silk Road economic belt.