The Hurricane fault is a major and active normal fault located in the southwestern USA. This study utilizes the geochemistry and dating of calcite veins associated with the fault to characterize ancient groundwater flow. Results show that waters moving along the fault over the last 540 000 years were a mixture of infiltrating fresh water and deep, warm salty groundwater. The formation of calcite veins may be related to ancient earthquakes, and the fault influences regional groundwater flow.

This study focuses on the impact of major rift border faults on fluid circulation and hanging wall sediment diagenesis by investigating a well-exposed example in NE Greenland using field observations, U–Pb calcite dating, clumped isotope, and minor element analyses. We show that fault-proximal sediments became calcite cemented quickly after deposition to form a near-impermeable barrier along the fault, which has important implications for border fault zone evolution and reservoir assessments.

Knowledge of subsurface velocities is key to understand how earthquake waves travel through the Earth. We present a method to construct velocity profiles for the upper sediment layer on top of the Groningen field, the Netherlands. Here, the soft-sediment layer causes resonance of seismic waves, and this resonance is used to compute velocities from. Recordings from large earthquakes and the background noise signals are used to derive reliable velocities for the deep sedimentary layer.

Mantle and lithospheric dynamics, elasticity, subsurface flow, and other fields involve solving indefinite linear systems. Tools include direct solvers (robust, easy to use, expensive) and advanced iterative solvers (complex, problem-sensitive). We show that a third option, ILDL preconditioners, requires less memory than direct solvers but is easy to use, as applied to 3D problems with parameter jumps. With included software, we hope to allow researchers to solve previously infeasible problems.

Analysing the genesis of Quaternary sediments is important for understanding the glaciation history and development of marine sediments in the northern part of Western Siberia. The key features of sedimentation and landform formation have been characterised for the first time in an example of a lithological column from the lower sources of the Nadym River. A comprehensive analysis was performed on the lithological, petrographic and geomorphological data from the upper Quaternary stratum.

The strength of fault rock plays a central role in determining the distribution of crustal seismicity. We review laboratory work on the physics of fault friction at low shearing velocities carried out at Utrecht University in the past 2 decades. Key mechanical data and post-mortem microstructures can be explained using a generalized, physically based model for the shear of gouge-filled faults. When implemented into numerical fault-slip codes, this offers new ways to simulate the seismic cycle.

In our work, we carry out an in-depth structural analysis of a geometrically decoupled fault system in the southern German Molasse Basin using a high-resolution 3-D seismic dataset. Based on this analysis, we reconstruct the tectonic history and changes in the stress regimes to explain the structure and evolution of faults. The results contribute in understanding the driving mechanisms behind formation, propagation, and reactivation of faults during foreland basin formation.

Through geological mapping we find that fault zone internal structure depends on whether or not the fault cuts multiple lithologies, the presence of shale layers, and the orientation of joints and coal cleats at the time of faulting. During faulting, cementation of fractures (i.e. vein formation) is highest where the fractures are most connected. This leads to the counter-intuitive result that the highest-fracture-density part of the network often has the lowest open-fracture connectivity.

Our rock deformation experiments (solid-medium Griggs-type apparatus) on wet assemblages of mafic compositions show that the ability of minerals to react controls the portions of rocks that deform and that minor chemical and mineralogical variations can considerably modify the strength of deformed assemblages. Our study suggests that the rheology of mafic rocks, which constitute a large part of the oceanic crust, cannot be summarized as being rheologically controlled by monophase materials.

This study focuses on the impact of deformation bands on fluid flow and diagenesis in porous sandstones in two different case studies (northern Apennines, Italy; Provence, France) by combining a variety of multiscalar mapping techniques, detailed field and microstructural observations, and stable isotope analysis. We show that deformation bands buffer and compartmentalize fluid flow and foster and localize diagenesis, recorded by carbonate cement nodules spatially associated with the bands.

We present new U–Pb age data to provide insights into the source of sediment for the Molasse Sedimentary Basin in Switzerland. The paper aims to help shed light on the processes that built the Central Alpine Mountains between ~35 and ~15 Ma. A primary conclusion drawn from the results is that at ~21 Ma there was a significant change in the sediment sources for the basin. We feel this change indicates major tectonic changes within the Central Alps.

We studied the characteristics of fracture systems in the Devonian rocks of the Orcadian Basin in Caithness. These mineral-filled fractures have properties that may be used to predict the size and spatial arrangement of similar structures in offshore basins. This includes the Clair field in the Faroe–Shetland Basin.

The injection of fluids (like wastewater or CO₂) into the subsurface could cause earthquakes when existing geological faults inside the reservoir are (re-)activated. To assess the hazard associated with this, previous studies have conducted experiments in which fluids have been injected into centimetre- and decimetre-scale faults. In this work, we analyse and model these experiments. To this end, we propose a new approach through which we extract the model parameters that govern slip on faults.

This study assesses the influence of basement rocks on the fluid chemistry during deformation in the Pyrenees and provides insights into the fluid regime in the NE part of the Iberian Peninsula.

The Sobrado unit represents an allochthonous tectonic slice of exhumed high-grade metamorphic rocks formed during a complex sequence of orogenic processes in the middle to lower crust. We have combined U–Pb geochronology and REE analyses (LASS-ICP-MS) of accessory minerals in migmatitic paragneiss (monazite, zircon) and mylonitic amphibolites (titanite) to constrain the evolution. A Middle Devonian minimum age for HP metamorphism has been obtained.

With computer simulations, we study the interplay between thermo-mechanical processes in the lithosphere and the underlying upper mantle during a long-term (> 100 Myr) tectonic cycle of extension–cooling–convergence. The intensity of mantle convection is important for (i) subduction initiation, (ii) the development of single- or double-slab subduction zones, and (iii) the forces necessary to initiate subduction. Our models are applicable to the opening and closure of the western Alpine Tethys.

The chronology of historical earthquakes (from historical documents and geological evidence) is still poorly constrained in the western Himalaya. We carried out a field investigation in SW Bhutan along the India–Bhutan border. Our analysis reveals that Bhutan has experienced at least five great earthquakes during the last 2600 years. Coseismic slip values along the Main Himalayan Thrust for most events reach at least 13 m and suggest that associated magnitudes are in the range of M_w 8.5–9.

A geochemical comparison of early Palaeozoic felsic magmatic episodes throughout the south-western European margin of Gondwana is analysed and includes data from the Iberian Massif, the Eastern Pyrenees, southern France and Sardinia. This dataset favours partial melting of sediments and/or granitoids in the lower continental crust during extensional movements related to the opening of the Rheic Ocean.

Fluids (like water or gases) within the Earth's crust often flow and interact with rock through fractures. The efficiency with which these fluids may flow through this void space is controlled by the width of the fracture(s). In this study, three different physical methods to measure fracture width were applied and compared and their predictive accuracy was evaluated. As a result, the mobile methods tested may well be applied in the field if a number of limitations and requirements are observed.

Processes associated with open pores can change the physical properties of rocks and cause earthquakes. In borehole samples from the Alpine Fault zone, we show that many pores in these rocks were filled by weak materials that can slide easily. The amount of open spaces was thus reduced, and fluids circulating within them built up high pressures. Both weak materials and high pressures within pores reduce the rock strength; thus the state of pores here can trigger the next Alpine Fault earthquake.

Our reactive transport models show that high-temperature fault-controlled dolomite can form from mixed convection and act as a sink for Mg in the circulating seawaters. This provides new perspectives to enhance understanding of mechanisms and controls on dolomitisation, geometry, and spatial distribution of dolomite bodies within faulted and fractured systems, which has important implications for modelling of systems ranging from geothermal resources to ore formation and carbonate diagenesis.

The Kallipetra Basin, formed in the Late Cretaceous on the reworked Pelagonian–Axios–Vardar contact in the Hellenides, is described for the first time. We document how and when the basin evolved in response to tectonic forcings and basin inversion. Cenomanian extension and basin widening was followed by Turonian compression and basin inversion. Thrusting occurred earlier than previously reported in the literature, with a vergence to the NE, at odds with the regional SW vergence of the margin.

Spatially continuous strain responses in two monitoring wells induced by a well-drilling process were monitored using high-resolution fiber-optic distributed strain sensing (DSS). The modeling results suggest that the strain polarities and magnitudes along the wellbores may be indicative of the layered-permeability structure or heterogeneous formation damage. The performance and value of DSS as a novel hydrogeophysical tool for in situ subsurface monitoring are emphasized.

In this work we provide a 2D finite-element modelling of the stress field conditions around the Fuego de Colima volcano (Mexico) in order to test the response of the commercial Linear Static Analysis software to increasingly different geological constraints. Results suggest that an appropriate set of geological and geophysical data improves the mesh generation procedures and the degree of accuracy of numerical outputs, aimed at more reliable physics-based representations of the natural system.

We present an innovative workflow for the statistical analysis of fracture data collected along scanlines. Our methodology is based on performing non-parametric statistical tests, which allow detection of important features of the spatial distribution of fractures, and on the analysis of the cumulative spacing function (CSF) and cumulative spacing derivative (CSD), which allows the boundaries of stationary domains to be defined in an objective way.

We identified several problems in Urbani et al. (2020), showing that their model does not conform to the age and location of faulting, identification and delimitation of uplifted areas and apical depressions, temperature and lithological well log, and stratigraphic and radiometric data. Published data indicate that the pressurization of the Los Humeros volcanic complex (LHVC) magmatic–hydrothermal system driving resurgence faulting occurs at a greater depth.

Using seismic array methods, 63 events were located in the Rodrigues–CIR region, not reported by any global network, most of them being off the ridge axis. The lack of seismicity along this section of the CIR, as observed from global data and this study, can possibly be attributed to the presence of partially molten mantle beneath Rodrigues Ridge. The results will be of interest for a broad range of geoscientists interested in the tectonic evolution of Indian Ocean and plume–crust interaction.