The Study On The Formation Mechanism Of Ground Fissures In Ying Country, Shanxi Province

The research of Shanxi graben basin ground fissures in recent years has got fruitfulresults. However, the research of ground fissures in Datong Basin was focused in Datongurban area, few researches of ground fissures was made in the southern basin.This article focus on a1.1km long, newly discovered ground fissure in Ying County, ShiZhuang Village, Shuo Zhou City, southern margin of the Datong Basin. Through a detailedfield survey and seismic, geological, hydrological data analysis, we obtained thecharacteristics of flat, profile and activities of this fissure. And based on all this information,we excavate two trenches, reveal the dislocations and formation caused by the fissure. In theflat view, the ground fissure enter the village from the southwest, the direction is theNEE-SWW,after through the scraped primary school the fissure’s strike changed to the northand at last went out of the village’s northwest corner at a direction of NEE, close toE-W.The fissure’s strike have changed twice. In the section of the Primary-trench, the westside strata of the fissure dropped; in the section of the Village-northwest-corner-trench, thesouth side strata of the fissure dropped and there is a regionel subsidence in the southwest sideof the village. After analysis, the type of Shi Zhuang Village fissure was identified as activefaults successional ground fissure. It is the earth surface outcrops of the secondary faults ofXiao Shikou active fault and Northern-Foothill-Liu Leng active fault. The trenches revealedthat deep strata vertical dislocation is more than3.15m and the shallow strata verticaldislocation is only15cm, this phenomenon is exactly the characteristics of active faultssuccessional type ground fissures. Hydrological data show that on the west of Village, thereshould be a groundwater cone of depression near Ying county and Shi Zhuang village justbelong to the Groundwater decline funnel edge, the tension area. So under the geologicalconfiguration of the two existing cracks, the fissure’s strike at the intersection area haschanged：from nearly N-S—the strike of Xiao Shikou active faults successional type groundfissure—towed and moved to NEE—the strike of the secondary of Northern-Foothill-LiuLeng active fault successional type ground fissure. This change graphically represente as the crack’s strike has a big angle alteration. The fissure’s recent movements which caused greatdamage is mainly due to seismic activities and exploitation the groundwater unilaterally.The results of this study provide some references for follow-up and further study of theDatong Basin and the whole Fen Wei basin ground fissures.