Investigating and processing of ground penetrating radar (GPR) sections in order to identify high-risk areas of subsidence and sinkholes in the alluvial sedimentary plain of Abarkooh, Yazd

Natural hazards are one of the factors that cause financial loss every year, and they occur in most regions of the world, including Iran. One of the hazards that mankind has been dealing with in recent decades, especially in alluvial plains is the phenomenon of land subsidence and sinkhole. Land subsidence and sinkhole due to natural and human causes have been reported in many places. Subsidence or sinkhole will damage human structures that are supported by the earth. Land subsidence is the most important environmental problem in Iran. A major cause of this phenomenon is overexploitation of underground water resources has led to land subsidence, and underground water extraction plays an important role in causing land subsidence. The study area is Abarkooh plain with an area of about 250 square kilometers is a part of the Eqlid-Abarkooh watershed. The lowlands are covered by Quaternary alluvial and some older sediments such as unconsolidated conglomerate, clayey, sandy, and saline areas. Based on geographical location, the study area is located in the geographical range of 53 degrees to 53 degrees and 32 minutes east longitude and 30 degrees and 50 minutes to 31 degrees and 12 minutes north latitude. This area contains medium to fine alluvial fan sediments that end in the salt playa or Abarkooh desert. To determine the high-risk and low-risk areas and routes in the study area, to discover subsurface holes and stratigraphic fractures underground up to a depth of 5 meters and the safe route for contracting works, etc., was used the ground penetrating radar (GPR) method. The results showed that in the areas where there are sinkhole traces in the determined distances around in current research, the attenuation signal of the ground penetrating radar, including the effects of subsurface cavities and stratigraphic fractures was discovered and revealed by GPR. On the side of the mountain slopes and high altitudes in the upstream region, no signal attenuation was observed, and sediments and soil were observed uniformly underground. The ultimate goal of the GPR section is to obtain a cross-section that is most consistent with the geological realities of the region and finally, at the final stage, we can talk about the characteristics, effects, and objectives of the research. The GPR method is an easy and low-cost method that is widely used in the field of natural resources and it is also used in other scientific fields. Regarding the common phenomenon of subsidence and sinkhole, these effects can be found underground, so that humans can prevent the development and expansion of this phenomenon. Also, this method can determine the route and safe area for contracting works, urban development, etc.