Turkey sits atop some of the most sinkhole-prone terrain in the world, and the problem has accelerated sharply this century. Central Anatolia’s Konya Basin alone saw sinkhole formation jump from roughly three per year in the early 2000s to more than thirty per year by the late 2010s, driven largely by decades of excessive groundwater pumping for agriculture. The geology, the water crisis, and the human decisions behind these collapses form an interconnected story that goes well beyond a simple hole appearing in the ground.
Why Central Turkey Is Sinkhole Country
Sinkholes need two basic ingredients: soluble rock underground and water moving through it. Turkey has both in abundance. Much of central and southern Anatolia is underlain by karst terrain, meaning the bedrock is made of limestone, gypsum, or other minerals that dissolve when water passes through them over long periods. As the rock dissolves, cavities and underground channels form. When the roof of a cavity can no longer support the weight above it, the surface collapses.
In the Upper Tigris Basin in southeastern Turkey, gypsum deposits from the Lower Miocene period have been extensively dissolved by aggressive groundwater flowing along fault lines. This dissolution created subsidence and surface depressions in the younger, loosely packed sedimentary layers above the gypsum.1Geomorphology. Land subsidence and caprock dolines caused by subsurface gypsum dissolution and the effect of subsidence on the fluvial system in the Upper Tigris Basin (between Bismil–Batman, Turkey) In the Konya Basin farther west, the bedrock is predominantly lacustrine limestone from the Neogene period, topped by loose Quaternary lake sediments. The combination of dissolving limestone below and weak sediments above makes this area especially collapse-prone.
Turkey’s karst landscapes are not limited to these basins. The country’s Mediterranean and Black Sea coastlines also sit on limestone, and researchers in Trabzon in the northeast have mapped karst cavities, water-saturated zones, and sinkhole structures across roughly three square kilometers of limestone terrain there.2Bulletin of Engineering Geology and the Environment. Deciphering of karst geomorphology and sinkhole (doline) structures using multiple geophysical and geological methods (Trabzon, NE Türkiye) In Antalya on the southern coast, tufa formations harbor air-filled cavities that researchers have detected using electrical resistivity methods.3Applied Sciences. Detecting Karstic Cavities Utilizing Electrical Resistivity Imaging (ERI) in Antalya, Türkiye In short, soluble rock formations span much of the country, and sinkholes are a geographically widespread hazard rather than a problem confined to a single region.
The Groundwater Connection
While Turkey’s geology sets the stage, falling groundwater levels pull the trigger. Underground water does more than dissolve rock over millennia. In the shorter term, it helps support the roof of any cavity that has already formed. When the water table drops, that buoyant support vanishes. Rock and sediment that were stable while saturated can suddenly collapse under their own weight.
The Konya Closed Basin is the starkest illustration. This endorheic basin has no outlet to the sea, so whatever water enters it stays there unless it evaporates or gets pumped out. And pumping has been relentless. Since the 1980s, groundwater levels across the basin have fallen by nearly 30 meters.4Groundwater for Sustainable Development. Navigating an impending crisis: Groundwater governance in Konya Closed Basin, Türkiye That decline was not gradual. An earlier study focused on the Karapınar area within the basin found that of a 24-meter total drop measured over 26 years, roughly a third occurred in just the final four years of the measurement period, between 2005 and 2008. During that same four-year window, 13 of the 19 sinkholes documented over the preceding three decades appeared.
The mechanism is straightforward: faster pumping creates steeper water-table declines, which destabilize more cavities in a shorter window. Since the early 2000s, many wells in the basin have shown accelerating drops, and sinkholes have become increasingly common as the land subsides.5Groundwater for Sustainable Development. Navigating an impending crisis: Groundwater governance in Konya Closed Basin, Türkiye
How Fast the Problem Grew
The numbers tell a striking story of escalation followed by a plateau. Between 2000 and 2010, the Konya Basin averaged about three new sinkholes per year. That rate climbed steadily, and by 2016 through 2019 the basin was producing around 32 sinkholes annually. Since 2020, the rate has fallen somewhat to about 22 per year.6Engineering Geology. Spatial-temporal patterns of sinkhole development in the Konya Basin, Türkiye. Implications for susceptibility and time-variant hazard assessment
That recent decline might sound like good news, but researchers attribute it to something more sobering than any improvement in water management: the region may be running out of easily collapsible cavities. The water table continues to fall, but many of the most vulnerable underground voids have already given way. Think of it like popping bubble wrap. The early pops come fast because there are plenty of intact bubbles. Eventually fewer remain, and the rate slows even though you are still pressing just as hard.
Spatially, new sinkholes tend to cluster near older ones. A susceptibility model built around the simple idea that future sinkholes form close to existing ones performed remarkably well. Buffer zones of 500 meters around sinkholes that appeared between 2011 and 2019 covered less than two percent of the total study area, yet those zones captured about 65 percent of the new sinkholes that opened between 2020 and 2024.7Engineering Geology. Spatial-temporal patterns of sinkhole development in the Konya Basin, Türkiye. Implications for susceptibility and time-variant hazard assessment This clustering makes intuitive sense: if one cavity collapses, the underground rock nearby likely has similar dissolution patterns and similar vulnerability.
Agriculture and the Demand for Water
Turkey’s sinkhole crisis cannot be separated from its agricultural economy. The Konya Basin is one of the country’s most productive farming regions, and irrigation is what keeps it that way. The basin is semi-arid with limited rainfall, so crops depend heavily on groundwater. As farming expanded and intensified over the past several decades, demand for irrigation water pushed well drilling deeper and pumping rates higher.
Groundwater modeling of the entire basin suggests that adopting more efficient irrigation technologies alone will not reverse the water-table decline. Only a combination of improved irrigation efficiency and a shift back toward traditional rainfed crops can meaningfully slow the overexploitation and protect the aquifer.8Hydrogeology Journal. Groundwater sustainability for irrigation in the semi-arid Konya Closed Basin, Türkiye, under climate change scenarios In other words, the problem is not just how water is applied to crops but which crops are grown in the first place.
This finding highlights a tension at the heart of the issue. Efficient irrigation sounds like a win-win, but it can actually encourage farmers to plant more water-intensive crops because each hectare now seems cheaper to water. Turkey experienced exactly this kind of backfire when it introduced a water-saving policy in late 2016. The policy tried to reduce agricultural water consumption by promoting water-efficient crops like lentils and chickpeas while requiring drip irrigation for corn growers. Instead, irrigated corn cultivation expanded significantly in the targeted regions. Farmers responded to rational economic signals: the subsidies for water-efficient crops were not large enough to compete with the higher profits from corn.9Australian Journal of Agricultural and Resource Economics. Unintended Effects of Water‐Saving Policy: Irrigated Corn Expansion in Türkiye
This outcome is a textbook example of what economists call the rebound effect. Making a resource cheaper to use per unit can increase total consumption. For Turkey’s sinkhole zones, it means that technical fixes to irrigation cannot stand alone. Without changing the economic incentives that drive crop choices, farmers will keep extracting groundwater at unsustainable rates, and the land will keep subsiding and collapsing.
How Researchers Detect Hidden Cavities
One of the most dangerous features of sinkholes is their unpredictability. The surface can look perfectly normal while a cavity is growing just meters below.10Natural Hazards. Sinkhole detection via deep learning using DEM images Turkish researchers have invested heavily in methods for finding voids before they open, and several geophysical techniques have proven useful.
Electrical resistivity imaging is one of the workhorses. The idea is that different underground materials conduct electricity differently. Solid rock, air-filled voids, and water-saturated zones each produce distinct resistivity signatures. In Antalya, researchers comparing resistivity data to known air-filled cavities in tufa formations found that the voids showed up clearly as zones of very high resistivity, on the order of 15,000 ohm-meters, making them straightforward to distinguish from surrounding rock.11Applied Sciences. Detecting Karstic Cavities Utilizing Electrical Resistivity Imaging (ERI) in Antalya, Türkiye
In more complex terrain, researchers deploy multiple methods simultaneously. At study sites in Trabzon’s limestone karst, a combination of electrical resistivity tomography, self-potential measurements, seismic refraction tomography, surface-wave analysis, and ground-penetrating radar was used to build a detailed picture of underground cavities and water-saturated zones.12Bulletin of Engineering Geology and the Environment. Deciphering of karst geomorphology and sinkhole (doline) structures using multiple geophysical and geological methods (Trabzon, NE Türkiye) Each method has strengths and blind spots, so stacking them together produces a more reliable map than any single technique would.
More recently, researchers have begun applying deep learning to digital elevation model imagery to identify sinkhole-prone terrain from satellite data.13Natural Hazards. Sinkhole detection via deep learning using DEM images This approach scales far more easily than ground-based geophysical surveys, which require equipment and field teams at every site. By training algorithms on the surface signatures of known sinkholes, researchers hope to flag high-risk areas across large regions without needing to visit each one individually.
Living With Sinkholes on the Ground
For the people who farm and live in sinkhole-prone parts of Turkey, these geological events are not abstract hazards. A sinkhole that opens in a field destroys that patch of arable land permanently. A sinkhole near a road or building can threaten lives and infrastructure. The Obruk Plateau, east of Karapınar, takes its name from the Turkish word for sinkhole (“obruk”), reflecting how deeply the phenomenon is embedded in the local landscape. The plateau contains several hundred ancient sinkholes that formed naturally during the Quaternary, but the newer ones forming in recent decades are different: they are induced by human activity, primarily groundwater extraction, and they present direct hazards to life and property.
The economic pressure is real. Farmers in the region face a dilemma: their livelihoods depend on irrigated agriculture, but that very irrigation is destabilizing the ground beneath their feet. Shifting to rainfed crops would reduce income in the short term even if it preserved the land in the long term. And as the policy failure with corn subsidies showed, government incentive programs have so far struggled to redirect farming practices when market prices push in the opposite direction.
Groundwater governance in Turkey has its own complications. Legislation governing groundwater use has faced problems in both design and enforcement. The sheer number of wells, many of them unregistered, makes monitoring and regulation difficult across the basin. Researchers studying the Konya Basin’s water governance have described the situation as an impending crisis, with the gap between extraction and recharge growing wider each year.14Groundwater for Sustainable Development. Navigating an impending crisis: Groundwater governance in Konya Closed Basin, Türkiye
Ancient Sinkholes and the Geopark Idea
Not all of Turkey’s sinkholes are hazards. Some of the older, naturally formed ones are spectacular geological features. The Karapınar area east of Konya city center contains more than 20 large sinkholes, some filled with water and some dry, spanning a range of sizes and ages.15Konya Journal of Engineering Sciences. DÜNYADA KARSTİK JEOPARK TURİZMİ VE JEOPARK ÖNERİ ALANI: KARAPINAR (KONYA-TÜRKİYE) The water-filled ones in particular can be strikingly beautiful, with deep turquoise pools surrounded by steep rocky walls.
Researchers have proposed designating roughly 1,500 square kilometers around Karapınar as a geopark, a concept promoted by UNESCO in which regions of outstanding geological heritage are protected and promoted for education and tourism. The proposed area encompasses not only the sinkholes themselves but also surrounding geosites and archaeological and cultural heritage sites.16Konya Journal of Engineering Sciences. DÜNYADA KARSTİK JEOPARK TURİZMİ VE JEOPARK ÖNERİ ALANI: KARAPINAR (KONYA-TÜRKİYE)
The geopark idea represents an interesting pivot: rather than viewing sinkholes solely as threats, it frames them as geological heritage worth preserving and visiting. For a region struggling with the economic consequences of water depletion and land instability, geotourism could offer an alternative income stream that does not require further groundwater extraction. Whether a geopark designation could generate enough tourism revenue to offset agricultural income is an open question, but it points toward a different relationship with the landscape than the extraction-heavy model that created the current crisis.
What Makes Turkey’s Situation Unusual
Sinkholes occur all over the world wherever soluble bedrock and groundwater coexist. What sets Turkey apart, and the Konya Basin in particular, is the speed and scale of the human-induced acceleration. Going from three collapses per year to more than thirty in under two decades is not a gentle trend. It reflects a feedback loop: population growth and agricultural expansion drive pumping, pumping lowers the water table, a lower water table destabilizes cavities, and collapsing cavities destroy farmland, which puts pressure on remaining land and wells.
The basin’s endorheic nature makes the problem harder to solve. In a river basin, upstream conservation can improve downstream supply. In a closed basin, what you pump is gone. Climate projections for central Anatolia generally point toward warmer, drier conditions, which would reduce natural recharge and increase crop water demand simultaneously. The groundwater modeling work on the Konya Basin explicitly considered climate change scenarios and still found that only a combination of better technology and a fundamental shift in crop selection could stabilize the aquifer.17Hydrogeology Journal. Groundwater sustainability for irrigation in the semi-arid Konya Closed Basin, Türkiye, under climate change scenarios
The clustering pattern of new sinkholes near old ones offers one practical advantage for risk management. Land-use planners can identify the highest-risk zones relatively cheaply, using buffer analysis around known sinkhole locations rather than expensive geophysical surveys of every square meter. The finding that a two-percent sliver of the study area captured about two-thirds of new collapses suggests that targeted building and infrastructure restrictions in those zones could significantly reduce damage, even without solving the underlying water problem.18Engineering Geology. Spatial-temporal patterns of sinkhole development in the Konya Basin, Türkiye. Implications for susceptibility and time-variant hazard assessment Whether Turkish authorities adopt and enforce such restrictions is another matter, but the scientific tools to guide those decisions already exist.
Sinkholes Beyond the Konya Basin
Because most research attention has focused on the Konya Basin, it is easy to assume the sinkhole problem is confined there. It is not. The Upper Tigris Basin’s gypsum dissolution and subsidence affect areas between Bismil and Batman in the southeast, where the subsidence has altered the behavior of local rivers and streams.19Geomorphology. Land subsidence and caprock dolines caused by subsurface gypsum dissolution and the effect of subsidence on the fluvial system in the Upper Tigris Basin (between Bismil–Batman, Turkey) In the northeast, Trabzon’s limestone karst contains its own network of cavities and depressions. Along the southern coast, Antalya’s tufa formations harbor hidden voids that could threaten development in a rapidly urbanizing region.
Each area has distinct geology and different human pressures, but the underlying story is the same: soluble rock, moving water, and in many cases human activity accelerating the natural process. Turkey’s rapid urbanization adds another dimension. Coastal cities expanding into karst terrain may face sinkhole risks that have not yet been systematically mapped, and construction activity itself can alter drainage patterns in ways that accelerate subsurface dissolution. The geophysical detection techniques being refined in places like Trabzon and Antalya may prove critical for guiding development decisions in these areas before collapses occur rather than after.