GIS and AHP Map Earthquake Risk in Eastern Anatolia

Deep in the mountainous terrain of Eastern Anatolia, researchers have produced one of the most detailed earthquake risk maps ever created for a small rural district, and the results reveal a striking pattern: seismic danger in the region is not spread evenly across the landscape but is instead concentrated in a narrow, well-defined corridor along an active fault line. A team from Fırat University and the Elazığ Provincial Disaster and Emergency Management Directorate applied a geographic information system (GIS) combined with the Analytic Hierarchy Process (AHP) to the Çemişgezek District of Tunceli province, generating a spatially explicit risk assessment designed to guide evidence-based disaster planning before a major earthquake strikes rather than after.

The study, published in Frontiers in Environmental Science, began with a 30-meter-resolution ASTER digital elevation model and built every thematic layer from scratch within ArcGIS Pro. The researchers derived slope and landform maps from the elevation data, produced a drainage density map by modeling flow direction and drainage networks, and estimated groundwater depth by overlaying soil, precipitation, and drainage intensity data. Because high water tables increase the fluidity of loose alluvial sediments, groundwater depth was included as a proxy for liquefaction potential, the phenomenon in which saturated soil temporarily loses its strength and behaves like a liquid during strong shaking. Active fault maps and a catalog of historical earthquakes with magnitudes greater than 3.0, retrieved from Turkey’s disaster management agency AFAD for the period 2000 to 2025, completed the dataset.

At the heart of the analysis lies the Analytic Hierarchy Process, a multi-criteria decision-making framework developed by Thomas Saaty that breaks complex problems into pairwise comparisons. Experts in seismotectonics, geomorphology, GIS, and disaster management judged the relative importance of each risk factor on Saaty’s nine-point scale, and the judgments were aggregated using the geometric mean method. The resulting weights were then applied to the spatial layers through weighted overlay analysis to produce the final earthquake risk map. A consistency ratio of 0.0324 confirmed that the expert judgments were internally coherent, well below the 0.10 threshold that AHP methodology requires for scientific validity.

The two dominant factors shaping earthquake risk in Çemişgezek turned out to be distance from fault lines, which accounted for 39.53 percent of the total risk weighting, and lithology, the rock and soil type underlying the surface, which contributed 30.41 percent. Together these two criteria explain nearly 70 percent of the overall seismic threat. Groundwater potential carried a weight of 17.98 percent, while slope contributed 12.08 percent. The findings underscore a fundamental principle of seismic hazard assessment: where a structure sits relative to an active fault, and what kind of ground it stands on, matter far more than the steepness of the terrain or the amount of rainfall the area receives.

When the weighted overlay was complete, the risk map revealed a district divided into five classes. Very low-risk terrain covers 17.87 percent of the district’s 821 square kilometers, while low-risk areas encompass 43.92 percent. Medium-risk zones account for 36.74 percent, high-risk areas for 1.34 percent, and very high-risk zones for a mere 0.07 percent, equivalent to just one square kilometer. That single square kilometer of extreme danger clusters around the villages of Tekeli and Cihangir, where the active fault line runs directly beneath the settlements and where the highest-magnitude earthquakes in the regional record have been recorded. The alignment between the model’s predicted hot spots and the historical earthquake catalog provides strong validation of the approach.

By contrast, 61.81 percent of the district falls into the low or very low risk categories, largely because it lies far from the active fault segments and rests on geologically older, more consolidated formations. The town center of Çemişgezek itself sits within the low and medium risk classes. This spatial concentration of hazard presents both a challenge and an opportunity for planners: rather than distributing limited resources uniformly across the entire district, disaster management equipment, structural reinforcement programs, and emergency preparedness initiatives can be targeted precisely at the small but critical corridor where the fault line passes.

Yet the researchers emphasize that physical hazard is only part of the story. Çemişgezek’s population has declined steadily over recent decades, with rural villages emptying faster than the district center, leaving behind an aging population with reduced physical mobility and diminished capacity for self-organized emergency response. Many buildings in the district are old, poorly maintained, and constructed without modern seismic engineering standards. The ferry line crossing the Keban Dam Lake, which serves as the region’s primary connection to the outside world, passes through high-risk geological units, meaning that a significant earthquake could sever the district’s only transportation link and leave residents isolated from external aid.

The study frames earthquake risk not as a purely tectonic phenomenon but as a socio-spatial vulnerability shaped by the interaction of natural conditions and demographic change. Continuous emigration of younger residents has eroded local economic investment and institutional capacity, while the remaining elderly population is less able to evacuate or rebuild after a disaster. The researchers argue that effective risk reduction requires a combination of measures: relocating new settlements to safer ground, reinforcing existing structures in the high-risk corridor, raising public awareness of earthquake hazards, and developing alternative evacuation routes, including helicopter landing areas and water-based transport options, to compensate for the district’s dependence on a single vulnerable crossing.

The methodology has clear limitations. The model relies on open-access data with a spatial resolution that limits micro-level accuracy, and it does not incorporate building-level structural parameters such as construction age, number of floors, or load-bearing materials. Seismic engineering parameters like peak ground acceleration and Vs30 shear-wave velocity measurements were also absent. The researchers acknowledge that the resulting map is better described as a physical susceptibility assessment than a comprehensive risk model, and they recommend that future work integrate dynamic datasets, building inventories, and machine learning approaches to refine predictions further.

Nevertheless, the Çemişgezek study offers a replicable template for other small, isolated districts across Turkey and beyond. By demonstrating that earthquake risk can be spatially quantified with freely available satellite data and a transparent weighting procedure, the research provides local governments with a practical decision-support tool aligned with the United Nations Sustainable Development Goal 11 on sustainable cities and communities. The message is clear: even in places far from major population centers, the ground beneath one’s feet can be mapped, measured, and planned for, long before the next earthquake arrives.

Subject of Research: GIS-based multi-criteria earthquake risk assessment in Çemişgezek District, Tunceli, Türkiye

Article Title: Multi-criteria GIS analysis of earthquake risk and spatial resilience in Eastern Anatolia

Article References: Engin, F., Giyik, C., Şengün, M. T., & Kaya, A. Y. (2026). Multi-criteria GIS analysis of earthquake risk and spatial resilience in Eastern Anatolia. Frontiers in Environmental Science, 14, Article 1800445. https://doi.org/10.3389/fenvs.2026.1800445

Image Credits: AI Generated

DOI: 10.3389/fenvs.2026.1800445

Keywords: earthquake risk, GIS, AHP, Çemişgezek, Tunceli, fault proximity, lithology, liquefaction, disaster planning, spatial analysis, Eastern Anatolia, risk mapping