On February 6, 2023, two major earthquakes with magnitudes Mw = 7.7 and Mw = 7.6 struck southeastern Turkiye, causing catastrophic damage and loss of life across 11 provinces, including Malatya. This study focuses on documenting the geotechnical observations and structural damage in Dogansehir, one of the hardest-hit districts not only in Malatya but in the entire affected region. An overview of the-region's tectonic and geological background is presented, followed by an analysis of ground motion data specific to Malatya. A detailed examination of seismic data from stations near Dogansehir was provided to better understand the seismic demands during the earthquakes. The paper then provides insights into the geotechnical conditions, building characteristics, and a damage ratio map of Dogansehir. The influence of local tectonics and geology on the observed damage is analyzed, alongside an evaluation of the seismic performance of masonry and reinforced concrete structures. Dogansehir, located near the epicenters of the Kahramanmaras earthquakes, suffered major structural damage. This was due to the surface rupture occurring near the settlement areas, the establishment of the district centre on the alluvial soil layer and the deficiencies/errors in the building systems. Building settlements on or near active fault zones, as well as on soft soil, leads to serious consequences and should be avoided or require special precautions.

We study CO2 injection into a saline aquifer intersected by a tectonic fault using a coupled modeling approach to evaluate potential geomechanical risks. The simulation approach integrates the reservoir and mechanical simulators through a data transfer algorithm. MUFITS simulates non-isothermal multiphase flow in the reservoir, while FLAC3D calculates its mechanical equilibrium state. We accurately describe the tectonic fault, which consists of damage and core zones, and derive novel analytical closure relations governing the permeability alteration in the fault zone. We estimate the permeability of the activated fracture network in the damage zone and calculate the permeability of the main crack in the fault core, which opens on asperities due to slip. The coupled model is applied to simulate CO2 injection into synthetic and realistic reservoirs. In the synthetic reservoir model, we examine the impact of formation depth and initial tectonic stresses on geomechanical risks. Pronounced tectonic stresses lead to inelastic deformations in the fault zone. Regardless of the magnitude of tectonic stress, slip along the fault plane occurs, and the main crack in the fault core opens on asperities, causing CO2 leakage out of the storage aquifer. In the realistic reservoir model, we demonstrate that sufficiently high bottomhole pressure induces plastic deformations in the near-wellbore zone, interpreted as rock fracturing, without slippage along the fault plane. We perform a sensitivity analysis of the coupled model, varying the mechanical and flow properties of the storage layers and fault zone to assess fault stability and associated geomechanical risks. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

The deformation energy (Wd) of soil-like tectonic coal is crucial for investigating the mechanism of coal and gas outbursts. Tectonic coal has a significant nonlinear constitutive relationship, which makes traditional elastic-based models for computing Wd unsuitable. Inspired by critical state soil mechanics, this study theoretically established a new calculation model of Wd suitable for the coal with nonlinear deformation characteristics. In the new model, the relationship between energy and stress no longer follows the square law (observed in traditional linear elastic models) but exhibits a power function, with the theoretical value of the power exponent ranging between 1 and 2. Hydrostatic cyclic loading and unloading experiments were conducted on four groups of tectonic coal samples and one group of intact coal samples. The results indicated that the relationship between Wd and stress for both intact and tectonic coal follows a power law. The exponents for intact and tectonic coal are close to 2 and 1, respectively. The stress-strain curve of intact coal exhibits small deformation and linear characteristics, whereas the stress-strain curves of tectonic coal show large deformation and nonlinear characteristics. The study specifically investigates the role of coal viscosity in the cyclic loading/unloading process. The downward bending in the unloading curves can be attributed to the time-dependent characteristics of coal, particularly its viscoelastic behavior. Based on experimental statistics, the calculation model of Wd was further simplified. The simplified model involves only one unknown parameter, which is the power exponent between Wd and stress. The measured Wd of the coal samples increases with the number of load cycles. This phenomenon is attributed to coal's viscoelastic deformation. Within the same stress, the Wd of tectonic coal is an order of magnitude greater than that of intact coal. The calculation model of Wd proposed in this paper provides a new tool for studying the energy principle of coal and gas outbursts. (c) 2024 Published by Elsevier B.V. on behalf of China University of Mining & Technology. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

The creation of fractures in bedrock dictates water movement through the critical zone, controlling weathering, vadose zone water storage, and groundwater recharge. However, quantifying connections between fracturing, water flow, and chemical weathering remains challenging because of limited access to the deep critical zone. Here we overcome this challenge by coupling measurements from borehole drilling, groundwater monitoring, and seismic refraction surveys in the central California Coast Range. Our results show that the subsurface is highly fractured, which may be driven by the regional geologic and tectonic setting. The pervasively fractured rock facilitates infiltration of meteoric water down to a water table that aligns with oxidation in exhumed rock cores and is coincident with the adjacent intermittent first-order stream channel. This work highlights the need to incorporate deep water flow and weathering due to pervasive fracturing into models of catchment water balances and critical zone weathering, especially in tectonically active landscapes. The creation of fractures in bedrock facilitates water movement through the subsurface which breaks down rock creating porous soil and weathered bedrock. Water movement is vital for important processes like plant growth, streamflow, and groundwater recharge. However, understanding how fracturing, water flow, and rock weathering interact is challenging because the subsurface is difficult and expensive to measure. Here we use observations from drilling, water level monitoring, and geophysics to understand these interactions. Our results indicate that the subsurface is highly fractured due to the geologic and tectonic setting. The large number of fractures makes it easier for water to flow through the subsurface and causes chemical alteration of bedrock. This may cause water to flow outside of the catchment through the subsurface. This work highlights the role of geologic and tectonic processes in driving fracturing, which dictates the movement of water and subsurface weathering beneath Earth's surface. Deep weathering may be due to enhanced permeability and surface area from inherited rock damage from local geologic and tectonic conditions Weathering and water flow extend to the elevation of the adjacent first-order intermittent stream channel The deep weathering and fracturing front may allow for inter-basin water flow in headwater catchments

The Yuncheng Basin is part of the Fenwei Graben System, which has developed ground fissure hazards that have caused serious damage to farmland, houses, and roads and have brought about huge economic losses. Located in Wanrong County on the Emei Plateau in the northwestern part of the Yuncheng Basin in China, the Wangjiacun ground fissure is a typical and special ground fissure developed in loess areas, and its formation is closely related to tectonic joints and the collapsibility of loess. In order to reveal the formation and genesis of the Wangjiacun ground fissure, the geological background, developmental characteristics, and genesis pattern of the Wangjiacun ground fissures were studied in detail. A total of three ground fissures have developed in this area: a linear fissure (f1) is distributed in an NNE-SSW direction, with a total length of 334 m; a circular fissure (f2) is located near the pool, with a total length of 720 m; f2-1, a linear fissure near f2, has a fissure length of 110 m and an NE orientation. This study shows that tectonic joints in loess areas are the main controlling factors of the linear fissure (f1); differential subsidence in the pool caused by collapsible loess is the main source of motivation for the formation of the circular fissures (f2, f2-1), and tensile stresses produced by the edges of subsidence funnels lead to the cracking of shallow rock and soil bodies to form ground fissures (f2, f2-1). This study enriches the theory of ground fissure genesis and is of great significance for disaster prevention and the mitigation of ground fissures in loess areas.

In outdoor environment, the exterior walls surface of buildings always suffers from damages caused by ultraviolet radiations, temperature variation, abrasion and erosion phenomenon, dust pollution, and microbial adhesion: Thereby reducing their durability over time. In order to overcome these obstacles, the superhydrophobic coatings can be an advantageous solution to ensure long-term stable use by improving the exterior concrete walls durability. In this line, a fluorine-free water-repellent coating was developed through sol-gel method and successfully applied to concrete substrates by dip-coating technique. The coating was formulated with low surface energy polydimethylsiloxane (PDMS) and polymeric silica (PS) to simultaneously modify the microstructure and chemical properties of concrete substrate surface. The coated concrete substrate showed super-hydrophobicity with high water contact angle (WCA) over than 150 degrees. Besides, the self-cleaning property, mechanical robustness, stability under UV irradiations, resistance to temperature and humidity were investigated. The results indicated that the coated concrete substrate cannot be soiled by dust and can resist over than 300 cycles of abrasion test. It also presents resistance to temperature of 45 degrees C associated with a humidity of 80% during 720 hours and showed excellent resistance to prolonged exposure to UV irradiations during 1440 hours. Natural out-door aging tests have shown that the superhydrophobic coating is weather resistant.

Soil massif fracturing has a significant impact on change in engineering and geological conditions and, as a result, on stability of structures. Development of tectonic fracturing of local structures, taking into account the history of the process, its mechanism, resulting stresses in the massif and subsequent deformations of the rocks, led to a change in their structure, composition and strength characteristics, activation of hypergenesis and exogenous processes. The above circumstances require careful attention to identification of areas of increased fracturing, as the most dangerous in terms of risks during the construction of engineering structures. Field methods for assessing the fracturing of rock masses are laborious. It is not always possible to conduct instrumental surveys that allow solving the final problem - establishing patterns and sizes of damaged areas within local structures. The existing mathematical models for assessing fracturing, as a rule, are used to solve local problems: assessing the stability of developed pits, water content of rock masses, degree of fragmentation of individual blocks, etc. This information is not sufficient when assessing the areal distribution of weakened zones and clarifying their boundaries, since it does not take into account the history of the development of the structure, its parameters (dimensions, amplitude of the foundation block uplift, deformation properties of rocks). Aim. To develop a mathematical model of formation of the red -colored strata tectonic fracturing zones based on deformation criterion of destruction and mechanism of development of local structures. Results. The authors have developed a new mathematical model for predicting damage (fracturing) of terrigenous rocks of the red -colored strata that make up local structures, based on the mechanism of formation of local tectonic structures of the 3rd order and the deformation criterion of destruction. The paper introduces the mathematical dependencies that make it possible to predict the size (area) of taxa based on the data on the uplift amplitude of local structures. The results of the research can be used in assessing the fracturing of massifs composed of terrigenous rocks, and make it possible to judge the regularities in distribution of weakened zones within the entire massif being assessed.

Alluvial fans in southern Monglia occur along a group of narrow discontinuous mountain ranges which formed as transpressional uplifts along a series of strike-slip faults. They provide information on the nature of neotectonic activity in the eastern Gobi Altai range acid on palaeoclimate change. Alluvial fan formation was dominated by various geomorphological processes largely controlled by climatic changes related to an increase in aridity throughout late Quaternary times. Their sedimentology shows that initially they experienced humid conditions, when the sedimentary environments were dominated by perennial streams, followed by a period of increasing aridity, during which coarse fanglomerates were deposited in alluvial fans by ephemerial streams and active-layer structures were produced by permafrost within the alluvial fan sediments. With climatic amelioration during early Holocene times, the permafrost degraded and fan incision and entrenchment dominated. Sedimentation was then confined to the upper reaches of the fans, adjacent to steep mountain slopes, and within the entrenched channels. The alluvial fans have been neotectonically deformed, faulted and their surface warped by small thrust faults that propagate from the mountain fronts into their forelands. Localised uplift rates are in the order of 0.1 to 1 m Ka(-1). (C) 1997 John Wiley & Sons, Ltd.