Sinkhole formation induced by descending groundwater in a karst aquifer near a limestone quarry

This study presents case studies conducted in northeast Thailand, where sinkhole collapses have continuously occurred in certain areas. Rapid descent of groundwater in a karst aquifer has the potential to induce sinkhole collapses within the karst morphology. Field investigations have revealed surface expressions of potentially hazardous sinkholes associated with zones of groundwater depression and abandoned groundwater wells. 2D electrical resistivity tomography (ERT) profiles were executed along the trend of such sinkhole collapses. The ERT results were combined to outline potentially dangerous cavities and continuous fractures. Sinkhole collapses in this scenario are primarily induced by groundwater depression and rainfall. Groundwater flows through conduits connecting a quarry with a karst cavern network, and dewatering of the quarry reduces the surrounding groundwater level. Runoff from rainfall percolates within overburden and enters air-filled cavities. Additionally, quarry blasting activities may cause vibrations that trigger the formation of sinkholes. Observations of surficial collapse features were generally consistent with geophysical ERT-interpreted subsurface cavities and fractures. Consequently, implementing regulatory measures to restrict the depth of limestone quarrying that affects groundwater levels may be necessary to prevent sinkhole collapses. The sinkhole formation phenomenon underscores a critical link between groundwater fluctuations and the stability of karst landscapes. The models depict the stages of sinkhole formation in karst terrain, starting with the natural landscape, progressing through limestone quarrying and culminating in sinkhole collapse caused by quarry dewatering and a subsequent lowering of the water table. image