Research on tectonic causes of numerous ground fissures development mechanism and its unbalance distribution between eastern and western of Weihe basin

Based on the high precision GPS monitoring data from 2001 to 2008, the finite element dynamic model of Weihe basin is established combined with its tectonic characteristics. Using above model the regional crustal stress field characteristics is studied, and the intrinsic relationship between the tectonic stress field and numerous ground fissures of Weihe basin is also analyzed thoroughly. For the first time the inherent dynamic relationship between the tectonic stress field and numerous ground fissures of Weihe basin is revealed quantitatively by the spatial geodetic, And the root causes of its unbalanced distribution between eastern and western of Weihe Basin is also revealed.. The results show that the present crustal stress fields of Weihe basin have significant difference, the eastern part mainly shows extension stress field with NW-SE direction while the western part mainly shows compression stress field with NE-SW direction, and overall showed relatively sinistral movement trend, which has good inheritance with the regional previous long-term tectonic deformation. The analysis discloses that the regional tensional stress field with NW-SN direction is the power source mechanism of numerous ground fissures development in the central and eastern of Weihe basin, while the differences of tectonic stress fields is also the fundamental reason for cracks unbalanced development in the eastern and western of Weihe Basin. Further analysis shows that the ground fissures in the Weihe Basin have strong tectonic characteristic, they are shaped by active faults with creep slipping ruptured soil under above power source mechanism. It is believed that the results in this paper could provide important information for the prevention of basin ground fissures disasters and city safety constructions.