The Quaternary activity of the Estella diapir from the uplift record of fluvial terraces, pediments and cave sediments in the Western Pyrenees, Spain

This work analyses the Quaternary landforms, geomorphic changes and stratigraphic evidences of evaporite dissolution and halokinesis in the Estella salt diapir (Basque-Cantabrian Basin). The mapping of Quaternary deposits demonstrates that karstic subsidence and diapirism happen at the same time. The diapir geometry is characterised by a prominent 4.5 km-long fault scarp attributed to the uplift of the diapir and a fluvial gypsum escarpment along the northern and eastern diapir edges. The dissolution of the gypsiferous caprock is responsible for the development of a large number of collapse sinkholes, the local thickening of terrace deposits and a network of endokarstic conduits connected to saline springs that cause a notable increase in the salinity of the Ega river across the diapir (70% electrical conductivity increase). The 40 m vertical displacement of T4 terrace and P5 pediment deposits, the anomalous longitudinal profile of the old terraces, the deflection of infilled-valleys at the base of the fault scarp, the occurrence of wind gaps and the continuous lateral migration of the Ega river away from the diapir support salt upwelling since 644 ± 81 ka ago at a long-term, average uplift rate of 0.05–0.07 mm/yr. The 12 m offset of T8 terrace, the steepening of the Ega river floodplain and the tilting of the upper level and the antigravitative erosion genesis of the Longinos cave point to a faster diapir rising rate of 0.23–0.57 mm/yr in the last 36 ± 15 ka coinciding with a period of increasing river incision. The lack of tectonic activity in the region suggests that diapirism is enhanced by erosional unloading related to fluvial entrenchment. The thickening of pediment P5 supports the north-northeast flow of salt towards the river valley

Landslide-Triggering Factors in Korucak Subbasin, North Anatolian, Turkey

AbstractKorucak Creek Basin is located within upper course of the Yeşilırmak River Basin and southern Middle Karadeniz (Black Sea) section which is known to have the potential of landslide and flood risk. The purpose of identification of landslide-triggering factors is to highlight the regional distribution of potentially unstable slopes and to guide decision makers for regional planning purposes. We assessed morphometric parameters for landslide-triggering factors of Korucak Creek Basin using GIS (Geographical Information System). These parameters are Stream Power Index (SPI) and Compound Topographic Index (CTI). Moreover, slope and elevation values of the basin were classified and superposed over the geologic map. Landslide locations were identified from topographic maps and verified with field observation. The total catchment area of the basin is about 55 km2. More than half of the total basin is covered by metamorphic rock types such as schist, which has high permeability and weakness against erosion and is one of the main causes of the landslides. The results show that the main triggering factors are slope and lithology. Thus, northern and western of the Korucak subbasin are under the highest-risk landslide areas

Spatial and temporal patterns of land subsidence and sinkhole occurrence in the Konya endorheic basin, Turkey

The endorheic Konya Basin is a vast aggradational plain in Central Anatolia, Türkiye. It occupies a significant portion of Konya Province, covering approximately 50,000 km2. The basin is subjected to intense groundwater withdrawal and extensive agricultural activities with excessive irrigation. These activities have led to human-induced hazards, such as sinkholes and regional land subsidence. Although sinkhole occurrence mainly occurs in the Karapınar area, land subsidence is primarily observed in the central sector of Konya city, with 2 million inhabitants, as well as in various parts of the basin. This study focuses on determining the extent and rate of land subsidence throughout the basin, understanding sinkhole formation, and unraveling their relationship with anthropogenic activities. For this purpose, Interferometric Synthetic Aperture Radar (InSAR) analysis of Sentinel-1 data from 2014 to 2022 was conducted to identify and assess land subsidence. We also used the land cover data and groundwater-level information to better understand the spatial and temporal patterns of land subsidence and sinkhole occurrence. Additionally, the land cover data were used to resolve spatial–temporal variations in the cultivated area and urbanization, which are the main factors governing groundwater exploitation in the region. Our study identified widespread subsidence zones with rates as high as 90 mm/y. Groundwater overexploitation to sustain extensive agricultural operations is the main cause of the high rate of land subsidence. Additionally, it was discovered that the number of sinkholes has substantially increased due to anthropogenic influences, currently amounting to as many as 660