Detection of Haqlaniyah cave within carbonate stratigraphic sequence rocks using 2D resistivity imaging technique, Haditha, western Iraq

Abstract

The western desert of Iraq is characterized by a widespread karst phenomenon and caves. The study area is a site for the establishment of a primary school inAl- Haqlanighah village Haditha area, during leveling the land with a bulldozer, the ground collapsed, causing a hole with a diameter of up to two meters. Two-dimensional resistivity imaging has been applied to detect the depth and extent of the subsurface cave within carbonate rocks and along two cross-image lines in the array of Dipole-dipole and an electrode distance of 5 meters, each length of 105m. 2D Dipole-dipole imaging technique is obtained the inverse models which shows the resistivity variation between the anomalous of background resistivity of rocks and part of cavity is about 750:100 Ω.m. These models showed that the depth 11m at the cavity operator to the roof of cavity. While the actual depth at same location of this cavity measured of 11.35m approximately. The results of this study showed that the extension of the cave along the first track is 52 meters in a direction of west-east, 11 meters depth to the ceiling of the cave, 31-35 meters to the bottom of the cave. While the extension of this cave along the second track is 20 meters in a direction south-north, and the depth to the ceiling of the cave is 12 meters and 32-34 meters to the bottom of the cave. The stratigraphic succession of the study area, starting from bottom withAnah Formation, overlain by unconformity brecciated bed, ranging from 6 to 30m meters in thickness, followed by Euphrates Formation in the top. The unconformity layer is less cohesive than the rocks beneath and above it. So it was the best area for the caves to be formed as a result of dissolving its rocks by leaking rain water and groundwater. Therefore, it must be a pre-engineering preparation before starting any urban construction of the population in the study area or adjacent areas to avoid risks.