Search Results (73)

The Lower Kura Basin is a tectonically active sedimentary region of Azerbaijan where geological and hydrogeological conditions may favor geothermal fluid circulation. This study develops a Geographic Information Systems (GIS)-based multi-criteria framework for regional geothermal favorability mapping by integrating five spatial criteria: land surface temperature (LST), fault density, slope, drainage density, and elevation. LST was derived from cloud-masked Landsat 9 Collection 2 Level-2 surface-temperature products acquired during summer 2025, while the topographic and hydrological criteria were prepared using a 30 m digital elevation model. All thematic layers were standardized to a common 30 m grid and reclassified into five favorability classes using explicitly defined classification rules. Criterion weights were determined using the Analytic Hierarchy Process (AHP), and the resulting pairwise comparison matrix yielded a consistency ratio of 0.024, indicating acceptable internal consistency. LST and fault density received the highest weights because they represent surface thermal expression and potential structural controls on subsurface fluid circulation, respectively, whereas slope, drainage density, and elevation were treated as secondary or indirect criteria. The baseline model identified 3681.9 km², corresponding to 27.71% of the study area, as having high or very high geothermal favorability. Two alternative weighting scenarios were subsequently evaluated to assess the sensitivity of the model to criterion weights. Despite substantial changes in the weighting scheme, 3624.0 km² (27.27% of the study area) consistently remained within the high or very high classes across all three scenarios and were therefore interpreted as robust geothermal favorability zones. Geological consistency was assessed through spatial comparison with regional geological evidence and mapped mud-volcano occurrences, while faults were not treated as an independent validation dataset because fault density was included as a model criterion. The proposed framework supports the identification of priority areas for further geothermal investigation and may contribute to the broader development of clean and renewable energy resources in Azerbaijan. The identified zones represent priority areas for further geological, hydrogeological, geophysical, geothermal-gradient, and exploratory investigations rather than confirmed geothermal resources. Full article

This study investigates the geochemical behavior and transport mechanisms of Rare Earth Elements (REEs), Yttrium (Y), Zirconium (Zr), and Hafnium (Hf) in three natural water systems under reducing conditions: the Santa Barbara and Occhio dell’Abisso mud volcanoes and a sulphureous spring at Villafranca Sicula. A comprehensive fractionation approach was applied to isolate the truly dissolved fraction (TDF < 10 kDa), the colloidal fraction (10 kDa < CF < 450 nm), the suspended particulate matter (SPM > 450 nm), and the associated bottom sediments. Analytical results reveal that REE distribution is significantly influenced by redox conditions and solid–liquid interface processes. The absence of negative Cerium (Ce) anomalies and the presence of pronounced positive Europium (Eu) anomalies in the Santa Barbara and Occhio dell’Abisso waters suggest strongly reducing environments where Eu²⁺ stability is enhanced. Shale-normalized patterns indicate that, while SPM and sediment fractions often exhibit Middle REE (MREE) enrichment, linked to Mn-bearing and Fe-oxyhydroxide phases, the dissolved phase reflects dissolution processes governed by a non-CHARAC (CHarge-and-RAdius-Controlled) behavior. Furthermore, the study highlights a significant decoupling in the Zr/Hf and Y/Ho pairs. While these pairs remain coherent during magmatic processes, they undergo mutual fractionation in aqueous systems due to differential reactivity toward colloidal surfaces and organic ligands. Specifically, Zr/Hf ratios in the colloidal and dissolved fractions deviate from chondritic values, driven by the preferential scavenging of Hf onto mineral surfaces. These findings underscore the utility of REE and Zr-Hf systematics as high-resolution tracers for reconstructing water–rock interaction processes and elemental cycling in complex hydrological environments. Full article

2-Phosphoglycerate kinase (2PGK) and cyclic 2,3-diphosphoglycerate synthase (cDPGS) are key enzymes involved in the biosynthesis of cyclic 2,3-diphosphoglycerate (cDPG), an extremolyte known to stabilize proteins in hyperthermophilic Archaea. Using bioinformatics approaches, two candidate genes for each enzyme were identified from a range of thermophilic bacterial and archaeal genomes and metagenomes. Significantly, one gene pair derived from the Taman mud volcano metagenome represents the first indication of a bacterial cDPG biosynthesis pathway. The recombinant expression and purification of these enzymes paved the way to their biochemical and structural characterization. One 2PGK candidate displayed predominant ATPase activity, while the newly identified cDPGS variants demonstrated cDPG synthase activity. Moreover, one of the latter biocatalysts, Ts-cDPGS from the hyperthermophilic archaeon Thermococcus sibiricus, demonstrated a notable thermostability and its 3D structure was resolved at a resolution of 2.2 Å. These findings broaden our understanding of extremophilic enzyme systems and lay the foundation for biotechnological applications involving extremolyte production. Full article

This study presents the first integrated quantification of mud diapirism susceptibility in the Membrillal sector of Cartagena de Indias, Colombia, through a multidisciplinary approach combining geospatial, geotechnical, hydrogeochemical, and socio-structural analyses. Using GIS-based multicriteria modeling, household surveys (n = 240), and temporal satellite imagery from 2013 to 2024, the research identifies spatial and temporal dynamics of active mud volcano reactivation. Field sampling of vent waters and gases followed ISO/IEC 17025 and APHA–AWWA–WEF standards, revealing high-salinity fluids (TDS = 13,220 mg/L; EC = 20.4 mS/cm; pH = 8.0) with elevated chloride (6996 mg/L) and low sulfate (1.67 mg/L) under reducing conditions, though a significant charge-balance discrepancy (Na⁺ = 8 mg/L) indicates either sample dilution during the collection or presence of unmeasured cationic species, and low free-gas flux constrained by high-density brine sealing. Principal component analysis of 240 georeferenced dwelling surveys yielded dimension-specific reliability (α = 0.68–0.76) and strong spatial correlation (Spearman ρ = 0.61–0.87) between vent proximity and structural damage—46.9% of dwellings exhibited visible cracking, with 27.2% severe (width > 1.5 mm). Satellite differencing documented 233% increase in active vents (3→10) and 35% vegetation reduction correlated with informal settlement expansion into moderate-to-high susceptibility zones. Weighted overlay GIS modeling (validated Kappa = 0.82) classified four hazard classes; high-susceptibility zones (18% of the study area) encompassed all ten active vents. Findings underscore anthropogenic pressurization drivers—primarily surface loading from settlement densification—and the need for continuous InSAR deformation monitoring, piezometric observation, complete hydrogeochemical characterization (including alkalinity and unmeasured cations), and establishing early-warning thresholds for community risk mitigation. Full article

The South Sakhalin mud volcano (Sakhalin Island, Russia) emits HCO₃-Cl/Na-Mg water, emanates CO₂ prevailing over CH₄ in the gas phase, and extrudes mud bearing five carbonate mineral species. The study focuses on the distribution, diversity, and origin of the carbonate minerals from the mud volcano (MV) ejecta, in terms of carbon cycle processes. The data presented include a synthesis of field observations, compositions of MV gases and waters, chemistry of carbonate minerals, as well as stable isotope geochemistry of MV waters (δ¹³C, δD, and δ¹⁸O) and carbonates (δ¹³C and δ¹⁸O). The sampled MV waters are isotopically heavy, with δ¹⁸O = +5.7‰ to +7.5‰ VSMOW, δD = −18.0‰ to −11.0‰ VSMOW, and ¹³C (δ¹³C_DIC = +6.9‰ to +8.1‰ VPDB). This composition may be due to the dilution of basinal water with dehydration water released during the diagenetic illitization of smectite. Carbonates in the sampled mud masses belong to three genetically different groups. Mg-rich siderite, (Fe_0.54–0.81Mg_0.04–0.30Ca_0.05–0.23Mn_0.00–0.08)CO₃, disseminated in abundance throughout the mud masses, coexists with common calcite and sporadic ankerite. The trace-element chemistry of Mg-siderite, as well as the oxygen (δ¹⁸O = +34.4‰ to +36.8‰ VSMOW) and carbon (δ¹³C = −1.3‰ to +0.6‰ VPDB) isotopic signatures, confirms its authigenic origin. Siderite formed during early diagenesis of the Upper Cretaceous sandy and clayey marine sediments mobilized by mud volcanism in the area. Another assemblage, composed of dawsonite, siderite, and vein calcite (±kaolinite), represents altered arkose sandstones found as few fragments in the mud. This assemblage may be a marker of later CO₂ flooding into the sandstone aquifer in the geological past. The trace-element chemistry, particular morphology, and heavy C (δ¹³C = +5.5‰ to +7.0‰ VPDB) and O (δ¹⁸O = +39.1‰ to +39.5‰ VSMOW) isotope compositions indicate that aragonite is the only carbonate species that is related to the current MV activity. It crystallized in a shallow reservoir and was maintained by CO₂ released from rapidly ascending liquefied mud and HCO₃-Cl/Na-Mg-type of MV waters. Full article

On 22–23 April 2025, a seismic noise survey was conducted at the Maccalube di Aragona, a mud volcano field located in Sicily (southern Italy), with the aim of characterizing the background signal associated with vent activity and the shallow subsurface structure. The experiment, named DEMETRA (DEnse MaccalubE TRomino Acquisition), was carried out within the framework of the multidisciplinary INGV-PROMUD research project, which aims to identify key indicators of mud volcano activity and potential precursors of paroxysmal events. Ambient seismic noise was recorded at 21 sites using a three-component, 24-bit digital tromograph. Measurements were conducted with a dense spatial sampling scheme covering both vent areas and peripheral zones. Preliminary data analyses included spectral estimates, computation of horizontal-to-vertical spectral ratio (HVSR) curves and evaluation of the polarization patterns. The HVSR curves do not display clear amplification peaks but rather show deamplification at specific sites. The polarization patterns exhibit spatial consistency across the vent areas. In addition, transient signals were identified in the background noise at some sites; based on their spectral and polarization characteristics, these signals are possibly associated with degassing, mud emissions, or bubbling phenomena. The dense spatial coverage of the DEMETRA experiment provides a valuable dataset for investigating subsurface properties and dynamic processes in an active mud volcano environment. Full article

The Muji Fault Zone (MJF) in the northeastern Pamir Plateau hosts a well-developed non-volcanic geothermal system, characterized by widespread hot springs and mud volcanoes—where core processes of geothermal fluids, including atmospheric precipitation recharge, shallow crustal circulation, carbonate-driven water–rock interactions, and CO₂-rich fluid discharge, are tightly coupled with regional intense crustal deformation and frequent seismic activity. We collected and analyzed 22 geothermal water samples and 8 bubbling gas samples from the MJF periphery, finding that the geothermal waters are predominantly of the HCO₃-Ca·Mg hydrochemical type, with hydrogen (δD: −103.82‰ to −70.21‰) and oxygen (δ¹⁸O: −14.89‰ to −10.10‰) isotopes indicating atmospheric precipitation as the main recharge source. The Na-K-Mg ternary diagram classified the waters as immature, reflecting low-temperature water–rock interactions in the shallow crust (<3 km), while noble gas isotopes (³He/⁴He: 0.03–0.09 Ra, Ra = 1.43 × 10⁻⁶) and carbon isotopes (δ¹³C-CO₂) confirmed fluid origin from crustal carbonate dissolution; SiO₂ geothermometry estimated thermal reservoir temperatures at 67–155 °C. Long-term monitoring (May 2019–April 2024) of Tahman (THM) and Bulake (BLK) springs revealed significant pre-seismic anomalies: before the 2023 Tajikistan Ms7.2 and 2024 Wushi Ms7.1 earthquakes, Na⁺, Cl⁻, and SO₄²⁻ concentrations showed notable negative anomalies (exceeding 2σ of background values) with synchronous trends between the two springs. Integrating these findings, a “Fault-Spring-Mud Volcano-Earthquake” fluid response model was established, providing direct evidence of deep-shallow fluid coupling in mud volcano–geothermal fluid interactions. This study enhances understanding of the dynamic evolution of non-volcanic geothermal systems under tectonic stress and clarifies the mechanisms of hydrogeochemical variations in fault-controlled geothermal systems, offering a robust scientific basis for advancing research on tectonic–fluid interactions in active fault zones of the northeastern Pamir Plateau. Full article

Studying Geography and Geology in formal education involves learning about landforms, landscapes, and the importance of preserving Natural Heritage. Geomorphosites are valuable resources with significant educational potential, as they can help students understand Earth’s history, appreciate Natural Heritage, and recognize their cultural and historical connections to the territory. By analyzing the curricular contents of the educational systems in Spain and Italy, this research proposes a novel method, focused on formal education, to assess the didactic potential of geomorphosites. The assessment is based on (i) how representative geomorphosites are of physical processes, (ii) their potential to support interdisciplinary learning, (iii) the availability of didactic materials, and (iv) the possibility of applying field techniques. The results revealed varying levels of didactic suitability among the analyzed geomorphosites, with Ulaca Hill (Spain) and Nirano mud volcanoes (Italy) having the highest didactic potential, also allowing evaluation of their relevance across different educational stages. The application of the methodology in both the Spanish and Italian contexts, with minor adjustments, showed that this approach is readily adaptable to other educational systems. Overall, this study provides a transferable framework for integrating geomorphological heritage into formal teaching, promoting place-based learning and fostering awareness and conservation of Natural Heritage. Full article

The Niland Moving Mud Spring, located near the southeastern margin of the Salton Sea, represents a rare and evolving geotechnical hazard. Unlike the typically stationary mud pots of the Salton Trough, this spring is a CO₂-driven mud spring that has migrated southwestward since 2016, at times exceeding 3 m per month, posing threats to critical infrastructure including rail lines, highways, and pipelines. Emergency mitigation efforts initiated in 2018, including decompression wells, containment berms, and route realignments, have since slowed and recently almost halted its movement and growth. This study integrates hydrochemical, temperature, stable isotope, and tritium data to propose a refined conceptual model of the Moving Mud Spring’s origin and migration. Temperature data from the Moving Mud Spring (26.5 °C to 28.3 °C) and elevated but non-geothermal total dissolved solids (~18,000 mg/L) suggest a shallow, thermally buffered groundwater source influenced by interaction with saline lacustrine sediments. Stable water isotope data follow an evaporative trajectory consistent with imported Colorado River water, while tritium concentrations (~5 TU) confirm a modern recharge source. These findings rule out deep geothermal or residual floodwater origins from the great “1906 flood”, and instead implicate more recent irrigation seepage or canal leakage as the primary water source. A key external forcing may be the 4.1 m drop in Salton Sea water level between 2003 and 2025, which has modified regional groundwater hydraulic head gradients. This recession likely enhanced lateral groundwater flow from the Moving Mud Spring area, potentially facilitating the migration of upwelling geothermal gases and contributing to spring movement. No faults or structural features reportedly align with the spring’s trajectory, and most major fault systems trend perpendicular to its movement. The hydrologically driven model proposed in this paper, linked to Salton Sea water level decline and correlated with the direction, rate, and timing of the spring’s migration, offers a new empirical explanation for the observed movement of the Niland Moving Mud Spring. Full article

The Paratethyan South Caspian and Mediterranean Levant basins relate to the significant hydrocarbon provinces of Eurasia. The giant hydrocarbon reserves of the SCB are well-known. Within the LB, so far, only a few commercial gas fields have been found. Both the LB and SCB contain some geological peculiarities. These basins are highly complex tectonically and structurally, requiring a careful, multi-component geological–geophysical analysis. These basins are primarily composed of oceanic crust. The oceanic crust of both the South Caspian and Levant basins formed within the complex Neotethys ocean structure. However, this crust is allochthonous in the Levant Basin (LB) and autochthonous in the South Caspian Basin (SCB). This study presents a comprehensive comparison of numerous tectonic, geodynamic, morphological, sedimentary, and geophysical aspects of these basins. The Levant Basin is located directly above the middle part of the massive, counterclockwise-rotating mantle structure and rotates accordingly in the same direction. To the north of this basin is located the critical latitude 35° of the Earth, with the vast Cyprus Bouguer gravity anomaly. The LB contains the most ancient block of oceanic crust on Earth, which is related to the Kiama paleomagnetic hyperzone. On the western boundary of the SCB, approximately 35% of the world’s mud volcanoes are located; the geological reasons for this are still unclear. The low heat flow values and thick sedimentary layers in both basins provide opportunities to discover commercial hydrocarbon deposits at great depths. The counterclockwise-rotating mantle structure creates an indirect geodynamic influence on the SCB. The lithospheric blocks situated above the eastern branch of the mantle structure trigger a north–northeastward movement of the western segment of the Iranian Plate, which exhibits a complex geometric configuration. Conversely, the movement of the Iranian Plate induced a clockwise rotation of the South Caspian Basin, which lies to the east of the plate. This geodynamic ensemble creates an unstable geodynamic situation in the region. Full article

We present a method for 3D gravity inversion using ellipsoidal parametrization and Particle Swarm Optimization (PSO), aimed at estimating the geometry, density contrast, and orientation of subsurface bodies from gravity anomaly data. The subsurface is modeled as a set of prolate ellipsoids whose parameters are optimized to minimize the misfit between observed and predicted anomalies. This approach enables efficient forward modeling with closed-form solutions and allows the incorporation of geometric and physical constraints. The algorithm is first validated on synthetic models with Gaussian noise, successfully recovering complex multi-body configurations with acceptable uncertainty. A statistical analysis based on multiple PSO runs provides interquartile ranges (IQRs) to quantify inversion stability. The method is then applied to a real microgravity dataset from the Nirano Salse mud volcanoes (northern Italy) using a field acquisition strategy previously described in the literature. Unlike earlier studies based on commercial software, our inversion uses the ellipsoidal–PSO framework. The best-fitting model includes four ellipsoids (two low- and two high-density), reproducing the main features of the observed Bouguer anomaly with a prediction error of 20–25%. The inferred geometry suggests that fluid migration is controlled by fault-related damage zones rather than shallow reservoirs. This method is robust, interpretable, and applicable to both synthetic and real cases, with potential uses in geotechnical, volcanic, and hydrogeological studies. Full article

Azerbaijan is known as a hydrocarbon-rich region for its extensive mud volcanoes and complex tectonic settings. In this research, we analyzed a long-term InSAR time-series from Sentinel-1 SAR data spanning January 2017 to October 2024, which revealed the dynamics of active deformation and mud volcanoes. The study area, with its unique geological complexity characterized by rapid eruptions, subsurface pressure, and fault systems, is a one-of-a-kind natural laboratory for examining the interplay between tectonics and mud volcano activity. Based on extensive data collection, the results showed significant deformation on the primary mud volcanoes, such as Ayazakhtarma and Akhtarma-Pashaly. These patterns, characterized by observed subsidence and uplift, result from subsurface pressure fluctuations and hydrocarbon migration. Furthermore, the examination has demonstrated evidence of temporal deformation episodes intricately linked to the periodic buildup and release of subsurface pressures. A significant result of our study was the reactivation of faults and high deformation rate in almost all observed mud volcanoes during the February 2023 Türkiye Kahramanmaraş earthquakes (Mw 7.8 and 7.6). This dynamic far-field triggering effect reactivated faults and induced widespread deformation. This study indicates that the far-field triggering effect has uncovered deformation patterns that persist for several months after the earthquakes, reflecting prolonged subsurface adjustments. The findings demonstrate that mud volcanoes are subsurface fluid dynamics and tectonic stress indicators and have significant practical implications. Overall, the results provide important insights into the reaction of hydrocarbon-rich regions to seismic energy that can be directly applied to improve regional seismic hazard assessments and tectonic studies. By combining different geodetic data with geological interpretations, this work emphasizes the implication of monitoring hydrocarbon-rich regions like Azerbaijan to assess natural hazards and subsurface dynamics, making the research highly relevant and applicable. Full article

The systematic morphometric analyses of submarine mud volcanoes are widespread yet still poorly understood geological features. Our study reveals that submarine mud volcanoes show significant variability in size and geometry, independent of water depth. Specifically, the mean height-to-radius (H/R) ratio is ~0.14 ± 0.08 (±1σ). This study focuses primarily on submarine mud volcanoes in the Mediterranean, which account for approximately 58% of the dataset and include structures reaching heights of up to ~500 m with mean diameters of up to 8000 m. These edifices display a range of basal geometries, from sub-elliptical (e.g., North Alex, off the coast of Egypt) to super-elliptical (e.g., Alberto da Ottaviano in the Mediterranean Ridge Accretionary Complex). A comparative analysis of morphometric parameters distinguishes mud cones from mud pies globally, with the latter generally lacking large examples (mean diameter >10 km). The results suggest distinct evolutionary pathways, beginning with small simple cones (~100 m³ in volume), analogous to arc volcanoes in other geological settings. This study integrates fundamental marine geology with applied geohazard considerations, serving as an initial step toward enhancing shared knowledge of submarine mud volcanoes. By improving the understanding of their formation, morphometric variability, and spatial distribution, this research supports better-informed decisions regarding submarine geohazards. Full article

In this research, the mud diapirism phenomenon in the Membrillal sector in Cartagena is characterized to analyze its spatiotemporal evolution. The goal is to geomorphologically, geotechnically, and geologically characterize the area to zone regions with the greatest susceptibility to geological hazards and provide an updated diagnosis of the phenomenon. This study is conducted due to the risks that mud diapirism poses to infrastructure and the safety of local communities. Understanding the behavior of these structures is essential for designing effective mitigation measures and optimizing urban planning in areas affected by this phenomenon. The methodology used includes collecting secondary data and implementing geophysical, geotechnical, and laboratory tests. Among the techniques employed are the Standard Penetration Test (SPT), the excavation of test pits, and electrical resistivity tomography, which revealed mud deposits at different depths. Laboratory studies also evaluated the physical and mechanical properties of the soil, such as Atterberg limits, grain size distribution, moisture content, and expansion tests, in addition to physic-chemical analyses. Among the most relevant findings is the presence of four active mud vents and four mud ears, representing an increase compared to the previous study that only recorded three mud vents. The tests revealed mud deposits at 1.30 m and 10 m depths, consistent with the geotechnical results. Laboratory tests revealed highly plastic soils, with Liquid Limits (LL) ranging from 44% to 93% and Plastic Limits (PL) ranging from 14% to 46%. Soil classification showed various low- and high-plasticity clays (CL and CH) and silty clays (MH), presenting challenges for structural stability and foundation design. Additionally, natural moisture content varied between 15.8% and 89%, and specific gravity ranged from 1.72 to 2.75, reflecting significant differences in water retention and soil density. It is concluded that diapirism has increased in the region, with constant monitoring recommended, and the Territorial Planning Plan (POT) has been updated to include regulations that mitigate the risks associated with urban development in affected areas. Full article

Since their creation, geoparks have been among the fastest growing natural environments. Their attractiveness is one of the most important factors for the success of this natural destination. Despite their importance, a bibliometric analysis on geopark attractiveness is missing from the studied databases. The aim of this paper is to synthesise a heterogeneous body of knowledge of geoparks in terms of attractiveness, highlighting the evolution and breadth of the research field. To achieve this, the following objectives were set: (a) to adopt a method based on functions provided by the bibliometrix package to automatically combine databases, namely WoS, Scopus, PubMed and Dimensions, detailing the method used and (b) to analyse the bibliometric indicators in order to identify the trends in the literature and the possible directions for future research. The applied methodology was based on bibliometric analysis using R for non-coders. From the 707 documents retrieved, the validation process resulted in 349 eligible documents published between 2002 and 2024, on which the analysis was carried out. The current study elaborated a method and examined the key information on the topic trends, which were given by production performance, productivity trends, spatial analysis and abstract approach analysis. Additionally, strategic mapping of the conceptual context was performed. Thus, the result provides a description of the automatic method with practical applications. As discerned from the three-dimensional analysis (spatial, temporal and size), the emerging research directions within scientific creativity encompassed (1) forms of tourism practiced in geoparks, especially focused on ecotourism and volcanic tourism; (2) geomorphological features, mineral springs and mud volcanoes; (3) aesthetic aspects, scenic sites and mining heritage; and (4) methodology, data analysis and modelling methods across different regions and countries. Full article