Sinkholes are places of karst depression.
The rapid drop in groundwater level caused by anthropogenic effects also has an indirect impact on the development of the sinkhole, which has a dynamic karstification process and can be classified as a natural disaster.
Sinkholes, which were formerly not considered a hazard due to variables such as low population density, limited agricultural and industrial sectors, have now reached a point where they can endanger human life due to the expansion of these characteristics over larger areas.
In its sinkhole research, our institution employs the following approach index to determine possible karstic danger areas based on the formation mechanisms and development processes of karst depressions;
Landsat5 TM, ASTER Terra, and ALOS Palsar Radar interferometry satellite images are analyzed in Remote Sensing studies.
During geological surveys, the sediments where sinkhole projections on the surface are detected are thoroughly examined and mapped based on the rock type distinction. Research is being carried out to reveal the lateral and vertical facies alterations of the rocks, as well as precise rock type features. Lineament maps are constructed in great detail.
First, the level variations in the groundwater table are measured in the constructed observation network during hydrogeological surveys carried out to study the hydrogeological structure, which contains the most essential characteristics in the sinkhole and karstic development of the region. The hydrochemical characteristics of groundwater are also determined using the same monitoring network. While well and spring head analyses are done in the field, samples are taken in the laboratory for analysis. Pump tests for the aquifer properties of the rocks, as well as tracer tests if necessary, are conducted in the region's existing or freshly drilled boreholes.
Engineering geology investigations are conducted in areas identified as a result of the project site's overall study. In this context, observational evaluation of the lithologies forming the sinkhole is carried out; mechanical parameters such as developed instabilities, discontinuities, and weathering effects are investigated in these areas, and in-situ tests are carried out to indirectly determine the strength parameters of the lithologies where sinkholes occur. Blocks, bags, and water samples are gathered from the lithological units where the sinkholes are supposed to have formed in the second part of the investigation, and field and laboratory experiments are conducted in these. The core samples collected from the drilling work completed at the end of the investigation are also evaluated in the laboratory as part of the experimental studies.
Gravity (microgravity), Geoelectricity, and Ground Radar are the three principal disciplines studied. The methodologies utilized are being used to try to figure out the subterranean geometry of potholes, the sites of probable karstic cavities, their areal distributions, and the cover-base rock contact connections in the investigated areas.
A sinkhole mechanism study is carried out using the geological, geomorphological, and hydrogeological characteristics that influence the region's karstic development.
Drills are used in hydrogeology and geotechnical applications. During the drilling process, geophysical data is also tested.