Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2026Severity-Based Mapping of Land-Subsidence Hazard Zones and Critical Hotspots Using SBAS-InSAR and Spatial Statistics: The Konya Metropolitan Area, Turkey
Yalvac, Sefa; Bjelotomić Oršulić, Olga
Land subsidence induced by excessive groundwater withdrawal has become one of the most significant geohazards affecting the Konya Closed Basin, Turkey. Although previous studies have successfully monitored ground deformation using geodetic and remote sensing techniques, limited attention has been devoted to transforming deformation measurements into quantitative, spatially classified hazard information. This study presents a severity-based framework for delineating land-subsidence hazard zones and critical hotspots in the Konya metropolitan area by integrating SBAS-InSAR observations and spatial statistical analyses. A total of 82 Sentinel-1 SAR acquisitions (41 ascending and 41 descending images) acquired between January 2023 and May 2026 were processed using the Small Baseline Subset (SBAS) technique. Ascending and descending line-of-sight deformation measurements were combined to derive vertical deformation rates, which were integrated with spatial statistical indicators and a composite severity index to quantify deformation clustering and classify subsidence severity. Hazard zones and critical hotspot areas were delineated through severity-based classification and spatial connectivity analyses. The results reveal a continuous north–south-oriented subsidence deformation belt extending across the eastern Konya. Maximum vertical subsidence rates exceeded 230 mm/yr, while spatial statistical analyses confirmed strongly clustered and statistically significant deformation patterns. Severity-based hazard zonation identified four hazard classes and a continuous high-hazard corridor. Clustering analysis further identified a dominant hotspot belt covering approximately 160 km2, with mean subsidence rates of approximately 142 mm/yr. A sensitivity analysis of the composite severity index weighting scheme, the spatial statistical neighborhood distance, the DBSCAN clustering parameters, and the number of Jenks severity classes confirmed that the resulting hazard zones and critical hotspot belt are robust to reasonable parameter variations. The findings demonstrate that land subsidence in Konya is organized as a spatially continuous regional-scale deformation system rather than a collection of isolated subsidence centers. The proposed framework transforms InSAR-derived deformation measurements into quantitative, decision-support hazard information and provides a transferable methodology for land-subsidence hazard assessment in groundwater-stressed urban environments.
- MakaleAçık Erişim2024Monitoring Surface Deformations in a Fossil Landslide Zone and Identifying Potential Failure Mechanisms: A Case Study of Gümüşhane State Hospital
Alemdag, Selçuk; Yalvaç, Sefa; Bjelotomić Oršulić, Olga; Kara, Osman; Zeybek, Halil İbrahim; Bostanci, Hasan Tahsin; Markovinović, Danko
The escalating occurrence of landslides has drawn increasing attention from the scientific community, primarily driven by a combination of natural phenomena such as unpredictable seismic events, intensified precipitation, and rapid snowmelt attributable to climate fluctuations, compounded by inadequacies in engineering practices during site selection. Within the scope of this investigation, contemporary geodetic techniques using the GNSS were employed to monitor structural and surface deformations in and around a hospital edifice situated within an ancient fossil landslide region. Additionally, inclinometer measurements facilitated the determination of slip circle parameters. A subsequent analysis integrated these datasets to scrutinize both the hospital structure and its surrounding slopes. In addition to the finite element method, four different limit equilibrium methods (Bishop, GLE–Morgenstern–Price, Spencer, and Janbu) were used in the evaluation of stability. Since the safety number determined in all analyses was <1, it was determined that the slope containing the hospital building was unstable. The movement has occurred again due to the additional load created by the hospital building built on the currently stable slope, the effect of surface and groundwater, and the improperly designed road route. As a result of geodetic monitoring, it was determined that the sliding speed on the surface was in the N-E direction and was approximately 3 cm, and this situation almost coincided with inclinometer measurements.
- MakaleAçık Erişim2024Seismic Disturbances and Geodetic Effects: Unraveling the Impact of the Mw = 6.2 Petrinja Earthquake on the Croatian Positioning System CROPOS
Bjelotomić Oršulić, Olga; Varga, Matej; Yalvac, Sefa
A destructive Mw = 6.2 earthquake struck NW Croatia on 29 December 2020, ranking among the most hazardous events in the country in the last century. This study assesses the impact of the earthquake on the permanent geodetic stations of the Croatian national positioning system. Using a novel approach, we combined positioning station data with satellite radar data for the first time in a geodynamic study across Croatia. The analysis involved collecting daily solutions data from 11 nearby network stations as well as multi-temporal satellite images before and after the earthquake. The results reveal a significant co-seismic shift, with the Sisak reference station experiencing the largest displacement of 5 cm to the southeast. Stations up to 100 km from the epicenter exhibited horizontal shifts between 1 and 2.5 cm and vertical shifts between 2 and 4 cm. Satellite images confirmed the co-seismic effects on the permanent stations. The study establishes a strong correlation between geodetic and geological findings, suggesting that vertical displacements result from superficial deposit consolidation in the river plains due to the earthquake shaking, while positional displacement reflects tectonic block movements along the activated strike-slip fault system. The late 2020 earthquake may have further relaxed the accumulated strain on the Mt. Medvednica thrust fault system, which had ruptured in early 2020 with a lower magnitude than expected.