Abstract. A two-stage fuzzy inference system (FIS) is applied to prospectivity modelling and exploration-target delineation for REE deposits associated with carbonatite-alkaline complexes in western part of the state of Rajasthan in India. The design of the FIS and selection of the input predictor map are guided by a generalised conceptual model of carbonatite-alkaline-complexes-related REE mineral

A microphysics-based understanding of mechanical and hydraulic processes in clay shales is required for developing advanced constitutive models, which can be extrapolated to long-term deformation. Although many geomechanical tests have been performed to characterise the bulk mechanical, hydro-mechanical, and failure behaviour of Opalinus Clay, important questions remain about micromechanisms: how do

Abstract. The restrictions implemented to contain the spread of the COVID-19 pandemic during 2020 and 2021 have forced university-level educators from around the world to seek alternatives to residential physical field trips which constitute a fundamental pillar of geoscience programmes. The field-mapping course for 2nd year Geology BSc students from the Cardiff University was replaced with a virtual

The nature of compositional heterogeneity in Earth's lower mantle remains a long-standing puzzle that can inform about the long-term thermochemical evolution and dynamics of our planet. Here, we use global-scale 2D models of thermochemical mantle convection to investigate the coupled evolution and mixing of (intrinsically dense) recycled and (intrinsically strong) primordial heterogeneity in the mantle

Understanding diagenetic reactions in accreted sediments is critical for establishing the balance of fluid sources and sinks in accretionary prisms, which is in turn important for assessing the fluid pressure field and the ability for faults to host seismic slip. For this reason, we studied diagenetic reactions in deformation bands (shear zones and veins) within deep mud sediments from the Nankai accretionary

At laboratory timescales, rock salt samples with different composition and microstructure show variance in steady-state creep rates, but it is not known if and how this variance is manifested at low strain rates and corresponding deviatoric stresses. Here, we aim to quantify this from the analysis of multilayer folds that developed in rock salt over geological timescale in the Ocnele Mari salt mine

Abstract. Geological carbon sequestration provides permanent CO2 storage to mitigate the current high concentration of CO2 in the atmosphere. CO2 mineralization in basalts has been proven to be one of the most secure storage options. For successful implementation and future improvements of this technology, the time-dependent deformation behavior of reservoir rocks in presence of reactive fluids needs

We analysed the instrumental seismicity in a sector of the Po Plain (Italy) to define the baseline for seismic monitoring of a new underground gas storage plant that will use the depleted gas reservoir of Cornegliano Laudense, near Lodi. The target area – a square approximately 80 km × 80 km wide – is commonly considered aseismic. The analysed period, 1951–2019, includes all available instrumental

Abstract. The Stratigraphy, Structure, Tectonics (SST) course at James Madison University incorporates a capstone project that traverses the Mid Atlantic region of the Appalachian Orogen and includes several all-day field trips. In the Fall 2020 semester, the SST field trips transitioned to a virtual format, due to restrictions from the COVID pandemic. The virtual field trip projects were developed

Abstract. The increased interest in subsurface development (e.g., unconventional hydrocarbon, deep geothermal, waste disposal) and the associated (triggered or induced) seismicity calls for a better understanding of the hydro-seismo-mechanical coupling in fractured rock masses. Being able to bridge the knowledge gap between laboratory and reservoir scales, controllable meso-scale in situ experiments

Abstract. In Europe, formation of the Palaeozoic Variscan orogenic belt, and then the Mesozoic-Cenozoic Alpine-Carpathian orogenic belt led to a widespread inversion events within forelands of both orogenic domains. We used legacy 2D seismic data together with the newly acquired 3D seismic data that for the first time precisely imaged sub-Zechstein (i.e. sub-evaporitic) upper Palaeozoic succession

Basin-scale salt flow and the evolution of salt structures in rift basins is mainly driven by sub- and supra-salt faulting and sedimentary loading. Crustal extension is often accompanied and followed by thermal subsidence leading to tilting of the graben flanks, which might induce an additional basinward-directed driver for salt tectonics. We designed a new experimental analogue apparatus capable of

Abstract. We present new constraints from tectonic geomorphology and paleoseismology along the newly discovered Sharkhai fault near the capital city of Mongolia. Detailed observations from high resolution Pleiades satellite images and field investigations allowed us to map the fault in detail, describe its geometry and segmentation, characterize its kinematics, and document its recent activity and

We make a thorough review of geological and seismological data on the long-lived Schio-Vicenza Fault System (SVFS) in northern Italy and present for it a geodynamic and seismotectonic interpretation.The SVFS is a major and high-angle structure transverse to the mean trend of the eastern Southern Alps fold-and-thrust belt, and the knowledge of this structure is deeply rooted in the geological literature

Abstract. A brief, regional-scale review of the Late Cretaceous – Early Palaeogene inversion-related tectonic structures affecting the Sudetes and their foreland at the NE margin of the Bohemian Massif is presented and complemented with results of new seismic studies. The Sudetes expose Variscan-deformed basement, partly overlain by post-orogenic Permo-Mesozoic cover, containing a wide spectrum of

Coincident wide-angle and multi-channel seismic data acquired within the scope of the PAMELA Moz3-5 project allow us to reconsider the formation mechanism of East African margins offshore of southern Mozambique. This study specifically focuses on the sedimentary and deep-crustal architecture of the Limpopo margin (LM) that fringes the eastern edge of the Mozambique’s Coastal Plain (MCP) and its offshore

The Phanerozoic tectonothermal evolution of the SW slope of the East European Platform (EEP) in Poland is reconstructed by means of thermal maturity, low-temperature thermochronometry, and thermal modelling. We provide a set of new thermochronometric data and integrate stratigraphic and thermal maturity information to constrain the burial and thermal history of sediments. Apatite fission track (AFT)

In this work we have performed a detailed study of vectors to ore to a representative volcanic-rock-hosted replacive volcanogenic massive sulfide (VMS) deposit located in the northern Iberian Pyrite Belt (Spain), the Aguas Teñidas deposit. The investigated vectors include the following: (1) mineralogical zoning, (2) host sequence characterization and mineralized unit identification based on whole rock

In this study, we determine spectral characteristics and amplitude decays of wind turbine induced seismic signals in the far field of a wind farm (WF) close to Uettingen, Germany. Average power spectral densities (PSDs) are calculated from 10 min time segments extracted from (up to) 6 months of continuous recordings at 19 seismic stations, positioned along an 8 km profile starting from the WF. We identify

Abstract. We present the pre-stack depth imaging results for a case study of 3D reflection seismic exploration at the Blötberget iron-oxide mining site belonging to the Bergslagen mineral district in central Sweden. The goal of this case study is to directly image the ore-bearing units and to map its possible extension down to greater depths than known from existing boreholes. Therefore, we applied

Abstract. Volgo-Uralia is a Neoarchean easternmost part of the East European craton. Recent seismic studies of the Volgo-Uralian region provided new insights into the crustal structure of this area. In this study, we combine satellite gravity and seismic data in a common workflow to perform a complex study of Volgo-Uralian crustal structure which is useful for further basin analysis of the area. In

Theoretical approaches to earthquake instabilities propose shear-dominated source mechanisms. Here we take a fresh look at the role of possible volumetric instabilities preceding a shear instability. We investigate the phenomena that may prepare earthquake instabilities using the coupling of thermo-hydro-mechano-chemical reaction–diffusion equations in a THMC diffusion matrix. We show that the off-diagonal

Subduction and exhumation are key processes in the formation of orogenic systems across the world, for example, in the European Alps. For geophysical investigations of these orogens, it is essential to understand the petrophysical properties of the rocks involved. These are the result of a complex interaction of mineral composition and rock fabric including mineral textures (i.e., crystallographic

The contemporary stress state in the upper crust is of great interest for geotechnical applications and basic research alike. However, our knowledge of the crustal stress field from the data perspective is limited. For Germany basically two datasets are available: orientations of the maximum horizontal stress (SHmax) and the stress regime as part of the World Stress Map (WSM) database as well as a

The dynamics of growing collisional orogens are mainly controlled by buoyancy and shear forces. However, the relative importance of these forces, their temporal evolution and their impact on the tectonic style of orogenic wedges remain elusive. Here, we quantify buoyancy and shear forces during collisional orogeny and investigate their impact on orogenic wedge formation and exhumation of crustal rocks

Abstract. Improving the knowledge of seismogenic faults requires the integration of geological, seismological, and geophysical information. Among several analyses, the definition of earthquake focal mechanisms plays an essential role in providing information about the geometry of individual faults and the stress regime acting in a region. Fault plane solutions can be retrieved by several techniques

Abstract. Analysis of new detrital apatite fission-track (AFT) ages from modern river sands, published bedrock and detrital AFT ages, and bedrock apatite (U-Th)/He (AHe) ages from the Northern Apennines provide new insights into the spatial and temporal pattern of erosion rates through time across the orogen. The pattern of time-averaged erosion rates derived from AHe ages from the Ligurian side of

Abstract. The operations needed to decarbonise our energy systems increasingly involve faulted rocks in the subsurface. To manage the technical challenges presented by these rocks and the justifiable public concern over induced seismicity, we need to assess the risks. Widely used measures for fault stability, including slip and dilation tendency and fracture susceptibility, can be combined with Response

Abstract. We describe two previously unreported, 5–7 km long normal fault scarps (NFS) occurring atop fault-related anticlines in the coastal ranges of the Dinarides fold-and-thrust belt in southern Montenegro, a region under predominant contraction. Both NFS show well-exposed, 6–9 m high, striated and locally polished fault surfaces in limestones, documenting active faulting during the Holocene. Sharply

Using borehole-constrained 3D reflection seismic data, we analyse the importance of sub-salt, salt, and supra-salt deformation in controlling the geometries and the kinematics of inverted structures in the Danish Central Graben. The Danish Central Graben is part of the failed Late Jurassic North Sea rift. Later tectonic shortening caused mild basin inversion during the Late Cretaceous and Paleogene

Abstract. In the present study, structure of sedimentary basins in the Eastern Asia Arctic zone is analysed by employing the approach based on decompensative gravity anomalies. Two obtained models, differing in their initial conditions, provide thickness and density of sediments in the study area. They demonstrate essentially new details on the structure, shape and density of the sedimentary basins

To discover or delineate mineral deposits and other geological features such as faults and lithological boundaries in their host rocks, seismic methods are preferred for imaging the targets at great depth. One major goal for seismic methods is to produce a reliable image of the reflectors underground given the typical discontinuous geology in crystalline environments with low signal-to-noise ratios

Abstract. We present the content and scripting of an active tectonic lab-session conceived for third year undergraduate students studying Earth Sciences at Observatoire des Sciences de l’Univers of Lyon. This session is based on a research project conducted on the submarine Roseau active fault in Lesser Antilles. The fault morphology is particularly interesting to map as this structure in the deep

Abstract. The Bohemian Massif exposes structures and metamorphic rocks remnant from the Variscan Orogeny in Central Europe and is bordered by the Franconian Fault System (FFS) to the west. Across the FFS, possible presence of Variscan units and structures are buried by Permo-Mesozoic sedimentary rocks. We integrate existing DEKORP 2D seismic reflection, well and surface geological data with the newly

Abstract. In this research paper were applied methods which integrate geophysical and petrological data to the crustal and lithospheric structure in the Sergipano Belt, in the Southern Borborema Province, NE Brazil. These methods allowed us to unveil the main crustal features and their tectonic relationships with the crust-mantle interface (Moho), as well as the lithosphere-asthenosphere boundary (LAB)

We present a series of new open-source deep-learning algorithms to accelerate Bayesian full-waveform point source inversion of microseismic events. Inferring the joint posterior probability distribution of moment tensor components and source location is key for rigorous uncertainty quantification. However, the inference process requires forward modelling of microseismic traces for each set of parameters

Due to the low to moderate seismicity of the European Western Alps, few focal mechanisms are available in this region to this day, and the corresponding current seismic stress and strain fields remain partly elusive. The development of dense seismic networks in past decades now provides a substantial number of seismic records in the 0–5 magnitude range. The corresponding data, while challenging to

We present an extensive dataset of highly accurate absolute travel times and travel-time residuals of teleseismic P waves recorded by the AlpArray Seismic Network and complementary field experiments in the years from 2015 to 2019. The dataset is intended to serve as the basis for teleseismic travel-time tomography of the upper mantle below the greater Alpine region. In addition, the data may be used

Global seismic tomography has greatly progressed in the past decades, with many global Earth models being produced by different research groups. Objective, statistical methods are crucial for the quantitative interpretation of the large amount of information encapsulated by the models and for unbiased model comparisons. Here we propose using a rotated version of principal component analysis (PCA) to

Abstract. The Lower Cretaceous Bashijiqike Formation of Kuqa depression is ultra-deeply buried sandstone in fold-and-thrust belts. Few researches link diagenetic processes with structure. To fill this gap, a comprehensive analysis integrating diagenesis with structure pattern, fracture and in situ stress is performed following a structural diagenetic approach. The results show that the pore spaces

Abstract. Reactivation of pre-existing structures and their influence on subsequent rift evolution have been extensively analysed in previous researches on rifts that experienced multiple phases of rifting, where pre-existing structures were deemed to affect nucleation, density, strike direction and displacement of newly-formed normal faults during later rifting stage. However, previous studies paid

Construction of cavities in the subsurface is always accompanied by excavation damage. Especially in the context of deep geological nuclear waste disposal, the evolving excavation damaged zone (EDZ) in the near field of emplacement tunnels is of utmost importance concerning safety aspects. As the EDZ differs from the intact host rock due to enhanced hydraulic transmissivity and altered geomechanical

Abstract. Shallow, light to moderate magnitude earthquakes in stable continental regions can have a damaging impact on vulnerable surface constructions. In the coal area of the Hainaut province in Belgium, a century of shallow seismic activity occurred from the end of the 19th century until the late 20th century. This seismicity is the second largest source of seismic hazard in northwestern Europe

Controlled-source seismic exploration surveys are not always possible in nature-protected areas. As an alternative, the application of passive seismic techniques in such areas can be proposed. In our study, we show results of passive seismic interferometry application for mapping the uppermost crust in the area of active mineral exploration in northern Finland. We utilize continuous seismic data acquired

In partially molten regions inside the Earth, melt buoyancy may trigger upwelling of both solid and fluid phases, i.e., diapirism. If the melt is allowed to move separately with respect to the matrix, melt perturbations may evolve into solitary porosity waves. While diapirs may form on a wide range of scales, porosity waves are restricted to sizes of a few times the compaction length. Thus, the size

Normal incidence seismic data provide the best images of the crust and lithosphere. When properly designed and continuous, these sections greatly contribute to understanding the geometry of orogens and, along with surface geology, unraveling their evolution. In this paper we present the most complete transect, to date, of the Iberian Massif, the westernmost exposure of the European Variscides. Despite

Two borehole ground-penetrating radar (GPR) surveys were conducted during saline tracer injection experiments in fully saturated crystalline rock at the Grimsel Test Site in Switzerland. The saline tracer is characterized by an increased electrical conductivity in comparison to formation water. It was injected under steady-state flow conditions into the rock mass that features sub-millimeter fracture

Abstract. Fiber-optic distributed acoustic sensing (DAS) data finds many applications in wellbore monitoring such as e.g. flow monitoring, formation evaluation, and well integrity studies. For horizontal or highly deviated wells, wellbore fiber-optic installations can be conducted by mounting the sensing cable to a rigid structure (casing/tubing) which allows for a controlled landing of the cable.

Abstract. The faults system mapped in the northern Marche Apennines, the NW sector of Monte Nerone, Italy, shows many indications of recent activity. This area has been affected by some strong historical earthquakes, such as the Cagli earthquake of 1781, similar to seismic events close by affecting the southern Marche, Umbria, Lazio, and Abruzzi areas in recent years, we focused our investigation on

During lithospheric extension, localization of deformation often occurs along structural weaknesses inherited from previous tectonic phases. Such weaknesses may occur in both the crust and mantle, but the combined effects of these weaknesses on rift evolution remain poorly understood. Here we present a series of 3D brittle–viscous analogue models to test the interaction between differently oriented

Abstract. In 2018 and 2019, the STIMTEC hydraulic stimulation experiment was conducted at 130 m depth in the Reiche Zeche underground research laboratory in Freiberg/Germany. The experiment was designed to investigate the rock damage resulting from hydraulic stimulation and to link seismic activity and enhancement of hydraulic properties in strongly foliated metamorphic gneiss. We present results from

Central and western Europe were affected by a compressional tectonic event in the Late Cretaceous, caused by the convergence of Iberia and Europe. Basement uplifts, inverted graben structures, and newly formed marginal troughs are the main expressions of crustal shortening. Although the maximum activity occurred during a short period of time between 90 and 75 Ma, the exact timing of this event is still

Abstract. Dating syntectonic sedimentary sequences is often seen as the unique way to constrain the initiation, kinematics and rate of folding and the sequence of deformation in the shallow crust. Beyond fold growth however, deformation mesostructures accommodate the internal shortening of pre-folding strata before, during and after strata tilting. Absolute dating of mesostructures developed during

Abstract. The Danish-Polish Trough – a large Trans-European sedimentary basin stretching from Denmark, through Germany, to south-eastern Poland and even further to the south into Ukraine, had undergone an uplift during the Late Cretaceous, which in consequence resulted in its inversion and development into the Mid-Polish Anticlinorium. In many existing paleotectonic interpretations, SE Poland, i.e

Abstract. The investigated area of the NW Dinarides is located at the NE corner of the Adriatic microplate and is bordered by the Adriatic foreland, the Southern Alps, and the Pannonian basin. Its complex crustal structure is the result of interactions among different tectonic units, mainly the Eurasian plate and the Adriatic microplate. Despite numerous seismic studies in this tectonically complex

Abstract. Phyllosilicates are generally regarded to have a reinforcing effect on chemical compaction by dissolution-precipitation creep (DPC) and thereby influence the evolution of hydraulic rock properties relevant to groundwater resources, geological repositories as well as fossil fuel reservoirs. We conducted oedometric compaction experiments on layered NaCl-biotite samples to test this assumption

The use of distributed acoustic sensing (DAS) presents unique advantages for earthquake monitoring compared with standard seismic networks: spatially dense measurements adapted for harsh environments and designed for remote operation. However, the ability to determine earthquake source parameters using DAS is yet to be fully established. In particular, resolving the magnitude and stress drop is a fundamental

The region around the town Albstadt, SW Germany, was struck by four damaging earthquakes with magnitudes greater than 5 during the last century. These earthquakes occurred along the Albstadt Shear Zone (ASZ), which is characterized by more or less continuous microseismicity. As there are no visible surface ruptures that may be connected to the fault zone, we study its characteristics by its seismicity

The world experienced the beginning of the COVID-19 pandemic by the end of 2019 to the beginning of 2020. Governments implemented strategies to contain it, most based on lockdowns. Mexico was no exception. The lockdown was initiated in March 2020, and with it, a reduction in the seismic noise level was witnessed by the seismic stations of the national and Valley of Mexico networks. Stations located

Back-arc extension superimposed on mountain belts leads to distributed normal faults and shear zones interacting with magma emplacement within the crust. The composition of granitic magmas emplaced at this stage often involves a large component of crustal melting. The Miocene Aegean granitoids were emplaced in metamorphic core complexes (MCCs) below crustal-scale low-angle normal faults and ductile