EVALUATION OF THE SINKHOLE HAZARD AT ALISSAWIAH SOUTH OF QURAYAT GOVERNORATE, JOUF REGION, KINGDOM OF SAUDI ARABIA

Different types of sinkholes have been recognized in the Kingdom of Saudi Arabia (KSA). These sinkholes are of various sizes, shapes and occur at different depths. Their presence may create direct risk to the infrastructural facilities. Other types of sinkholes appeared mostly in a rural areas. This paper deals with the evaluation of the geological factors leading to the formation of sinkholes and their impacts on the land developments in Al Issawiah area, Al Jouf region in the northern part of the KSA. It promotes idea of karst region in the KSA, which represents a real geological hazard that affects a large area. The bases of the methodology take into account the description, interpretation and analysis of the fundamental geological information to determine the features related to karst formation. In addition, the vertical extent of the sinkholes as well as the subsurface layering and groundwater aquifer characteristics are explored by different geophysical techniques (electrical resistivity and gravity methods). On the other hand, applying the also drilling program is used to understand the subsurface stratigraphy and the geotechnical characteristics of the subsurface sediments that are affected by the formation of sinkholes. Finally, establish a hazard zonation map is prepared by using Geographic Information System (GIS) for the areas that are potentially susceptible to sinkholes.
The field investigations and measurements enable the authors for the detection of two collapsible sinkholes in the study area (about 200 km2 on a scale of 1:50,000).