New acquisition styles for active seismic source exploration provide a wealth of additional quasi-passive data. We show how these data can be used to gain complementary information about the subsurface. Specifically, we process an active-source dataset from an alpine valley in western Colorado with both active and passive inversion schemes. The results provide new insights on subsurface hydrology based on the ratio of P-wave and S-wave velocity structures.

We quantify the effects that 3-D fractures with realistic distributions of aperture have on seismic wave attenuation and velocity dispersion. Attenuation and dispersion are caused by fluid pressure diffusion between the fractures and the porous background. We show that (i) both an increase in the density of contact areas and a decrease in their correlation length reduce attenuation and (ii) a simple planar fracture can be used to emulate the seismic response of realistic fracture models.

Earthquakes in the subsurface are hard to monitor due to their complicated signals. We aim to make the monitoring of the subsurface possible by redatuming the sources and the receivers from the surface of the Earth to the subsurface to monitor earthquakes originating from small faults in the subsurface. By using several sources together, we create complex earthquake signals for large-scale faults sources.

Salt basins are important as they bear abundant natural resources and record valuable geological information. However, some models of salt basin evolution do not fully reconcile with natural examples. Using state-of-the-art analogue modelling, we investigate how a relatively stable area, the translational domain, occurs and gets overprinted in salt basins. The results suggest that that variation of sediment deposition is the key factor for overprinting the translational domain.

3-D seismic reflection data reveal that deepwater volcanoes have rugged basal contacts, which truncate underlying strata, and erupted lava flows that feed lobate lava fans. The lava flows (>  9 km long) account for 50–97 % of the total erupted volume. This indicates that deepwater volcanic edifices may thus form a minor component (~ 3–50 %) of the extrusive system and that accurate estimates of erupted volume require knowledge of the basal surface of genetically related lava flows.

The formation of dolomite (CaMg(CO₃)₂), an abundant mineral in Earth's geological record, is still incompletely understood. We studied dolomites embedded in a 100 m thick succession of coastal alluvial clays of Triassic age in the southern Alps. Observation by light microscopy and Sr isotopes suggests that dolomites may spontaneously from concentrated evaporating seawater, in coastal ephemeral lakes or tidal flats along the western margin of the Triassic Tethys sea.

A 2-D numerical modelling approach to simulate the mechanical formation of sinkhole cluster inside large-scale karstic depressions is presented. Different multiple cavity growth scenarios at depth are compared regarding the mechanical process and collapse style. The outcomes of the models are compared to results from remote sensing and geophysics for an active sinkhole area in the Dead Sea region.

We present an updated geological map of the volcanic rocks present in the north-east Oman mountains. These volcanic rocks erupted at the seafloor, probably above a young subduction zone, and have since been tectonically transported into their accessible position. The updated map allows us to examine the spatial relationships between the different volcanic and geological features, including copper, gold, and chrome deposits. The new map will aid further study in Oman and other similar settings.

In projects based on enhanced geothermal system (EGS) technology, knowledge of the in situ stress state is of central importance to predict the response of the rock mass to different stimulation programs. We propose a characterization of the in situ stress state from the analysis of ultrasonic borehole imager (UBI) data acquired at different key moments of the reservoir. We discuss a significant stress rotation at depth and the absence of a significant change in the stress magnitude.

We propose innovative parametric modeling allowing for analysis of a very large number of fault-slip numerical simulations on 3-D discrete fault network. The approach allows for the first time producing failure envelopes of large rock volumes containing faults, using variations of geological conditions such as remote stresses, cohesion, friction, and fluid pressure. This tool helps to define the most conservative fault slip hazard case or to account for potential uncertainties in the input data.

Image correlation techniques have provided new ways to analyse the distribution in space and time of deformation in analogue models of tectonics. Here, we demonstrate how the correlation of successive time-lapse images of a deforming model allows calculating the finite displacements and finite strain tensor. We illustrate, using synthetic images, the ability of the algorithm to produce maps of the finite deformation.

Subduction-transform edge propagator (STEP) faults are the locus of continual lithospheric tearing at the edges of subducted slabs, resulting in sharp changes in the lithospheric thickness and triggering lateral and/or near-vertical mantle flow. Here, we study upper mantle rocks recovered from a STEP fault context by < 4 Ma alkali volcanism. We reconstruct how the microstructure developed during deformation and coupled melt–rock interaction, which are promoted by lithospheric tearing at depth.

This work was inspired by an effort to numerically reproduce laboratory models of extension tectonics. We tested various set-ups to find a suitable analogue model and in the process systematically charted the impact of set-ups and boundary conditions on model results, a topic poorly described in existing scientific literature. We hope that our model results and the discussion on which specific tectonic settings they could represent may serve as a guide for future (analogue) modeling studies.

Seismic reflection data allow us to infer subsurface structures such as horizon and fault surfaces. The interpretation of this indirect data source is inherently uncertainty, and our work takes a first look at the scope of uncertainties involved in the interpretation of 3-D seismic data. We show how uncertainties of fault interpretations can be related to data quality and discuss the implications for the 3-D modeling of subsurface structures derived from 3-D seismic data.

Shear zones dominated by hydrated mantle rocks (serpentinites) occur in many tectonic settings around the world. To better understand the internal structure, composition and possible mechanical behaviour of these shear zones, we performed a detailed field, petrological and microanalytical study of the Livingstone Fault in New Zealand. We propose a conceptual model to account for the main physical and chemical processes that control deformation in large serpentinite shear zones.

Data acquisition costs mainly borne by expensive vibrator machines (i.e., deployment, operations, and maintenance) can be regarded as the main impediment to wide application of seismic methods in the mining industry. Here, we show that drill bit noise can be used to image the shallow subsurface when it is optimally acquired and processed. Drill bit imaging methods have many applications in small scale near-surface projects, such as those in mining exploration and geotechnical investigation.

This study investigates approaches to implementing plate boundaries within a fluid dynamic framework, targeted at the evolution of subduction over many millions of years.

Ancient evaporite sequences were deposited as interlayered rocksalt, other evaporites, and non-evaporite rocks that have enormous differences in strength. Whereas the ductile layers flow during deformation, strong layers are folded and/or torn apart, with the intrasalt deformation dependent on the mode and history of salt tectonics. This has important implications for accurately imaging and interpreting subsurface seismic data and for drilling wells through evaporite sequences.

When carbon dioxide is introduced into the subsurface it will migrate upwards and can encounter faults, which, depending on their hydrogeological properties and composition, can form barriers or pathways for the migrating fluid. We analyse uncertainties associated with these properties in order to better understand the implications for the retention of CO₂ in the subsurface. We show that faults that form seals for other fluids may not be seals for CO₂, which has implications for storage sites.

Using geological and geophysical data, we set up a 3-D digital description of the underground structure in the central part of the Po alluvial plain. By means of computer-simulated propagation of seismic waves, we were able to identify the structural features that caused the unexpected elongation and amplification of the earthquake ground motion that was observed in the area during the 2012 seismic crisis. The study permits a deeper understanding of the seismic hazard in alluvial basins.

To understand the fate of carbon in subducted oceanic sediments and crust, we studied carbonate phases in rocks from the Mariana subduction zone. These show that carbon is liberated from the downgoing plate at depths less than 20 km. Some of the carbon is subsequently trapped in minerals and likely subducts to greater depths, whereas fluids carry the other part back into the ocean. Our findings imply that shallow subduction zone processes may play an important role in the deep carbon cycle.

Our goal is to better understand the evolution of the Earth's outer shell in northeast Brazil. We analyze the propagation properties (anisotropy) of distant seismic waves in order to look for subsurface, large-scale deformation structures. Results show that structures visible at the surface can be traced down to ~100  km depth, that the imprint of the opening of the Atlantic Ocean can be detected along the coast and that the continental interior is anomalous due to a complex deformation history.

To meet the goal of the Paris Agreement to limit temperature increase below 2 ºC, geologic carbon storage (GCS) will be necessary at the gigatonne scale. But to successfully deploy GCS, seismicity induced by CO₂ injection should be controlled and maintained below a threshold that does not generate nuisances to the population. We conclude that felt induced seismicity can be minimized provided that a proper site characterization, monitoring and pressure management are performed.