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The 2 June 1994 Java tsunami earthquake ruptured in a seismically quiet subduction zone and generated a larger-than-expected tsunami. Here, we re-process a seismic line across the rupture area. We show that a subducting seamount is located up-dip of the mainshock in a region that did not rupture during the earthquake. Seamount subduction modulates the topography of the marine forearc and controls the seismic slip propagation during the earthquake by deflecting the rupture around the seamount.

New images from the multi-national AlpArray experiment illuminate the Alps from below. They indicate thick European mantle descending beneath the Alps and forming blobs that are mostly detached from the Alps above. In contrast, the Adriatic mantle in the Alps is much thinner. This difference helps explain the rugged mountains and the abundance of subducted and exhumed units in the core of the Alps. The blobs are stretched remnants of old ocean and its margins that reach down to at least 410 km.

Sediments accumulated in accretionary prims are deformed by the compression imposed by plate subduction. Here we show that deformation of the sediments transforms some minerals in them. We suggest that these mineral transformations are due to the proliferation of microorganisms boosted by deformation. Deformation-enhanced microbial proliferation may change our view of sedimentary and tectonic processes in subduction zones.

We analyze folded multilayer sequences in the Ocnele Mari salt mine (Romania) to gain an insight into the long-term rheological behavior of rocksalt. Our results indicate a great role of even a small amount of impurities in the rocksalt on its effective mechanical behaviour. We demonstrate how the development of folds that develop at various scales can be used to constraining the viscosity ratio in the deformed multilayer sequence.

The Ligurian Sea opened ~30–15 Ma during the SE migration of the Calabrian subduction zone. Using ambient seismic noise from stations on land and at the ocean bottom, we calculated a 3D shear-velocity model of the Ligurian Basin. We find a shallow crust-mantle transition at the southwestern basin centre that deepens towards the Liguro-Provencal coast. We see no evidence for an Alpine slab beneath the basin. However, a separation of SW and NE basin appears to prolong the onshore Alpine front.

The Alpine mountain belt was formed by the collision of the Eurasian and African plates in the geological past, during which parts of the colliding plates sank into the Earth's mantle. Using seismological data from distant earthquakes recorded by the AlpArray Seismic Network, we have derived an image of the current location of these subducted parts in the Earth's mantle. Their quantity and spatial distribution is key information needed to understand how the Alpine orogen was formed.

The seismicity of Fogo and Brava, Cape Verde, is dominated by volcano-tectonic earthquakes in the area of Brava and volcanic seismic signals, such as hybrid events, on Fogo. We locate these events using a multi-array analysis, which allows the localization of seismic events occurring outside the network and of volcanic signals lacking clear phases. We observe exceptionally high apparent velocities for the hybrid events, located on Fogo. These velocities are likely caused by a complex ray path.

We have performed a detailed study of the rocks surrounding a major Zn-Pb-Cu ore deposit in southwest Spain in order to characterize the behavior of chemical elements in the influence area of the hydrothermal system that produced the deposit. Based on this information we propose new ways of detecting the nearby presence of ore deposits of this kind during exploration, thus improving our ability to detect new resources and contributing to securing the future supply of metals for our society.

The long-lived Schio-Vicenza Fault System is a major shear zone cross-cutting the foreland and the thrust belt of the Eastern Southern Alps. We review 150 years of scientific works, and explain its activity and kinematics, characterised by sinistral and dextral transcurrent motion along its southern and northern sections, respectively, by a geodynamic model that has the Adria indenter as the main actor, and coherently reconciles the available geological and geophysical evidence collected so far.

An experimentally-deformed sample of Opalinus Clay, considered as host rock for nuclear waste in Switzerland, was studied by electron microscopy to image deformation microstructures. Observations showed that deformation localized by forming micrometre-thick fractures. Deformation zones show dilatant micro-cracking, granular flow and bending grains, and pore collapse. Our deformation model with three different stages of damage accumulation illustrates the mechanics in a compressed OPA sample.

Rock fractures are organized as networks with spatially varying arrangements. Owing to networks' influence on bulk rock behavior, it is important to quantify network spatial variation. We utilize an approach where fracture networks are treated as spatial graphs. By combining graph similarity measures with clustering techniques, spatial clusters within large-scale fracture networks are identified and organized hierarchically. The method is validated on a dataset with nearly 300,000 fractures.

In the first part of this article, we present a new methodology that we have developed to model the deformation and the microstructural evolutions of olivine rocks, which compose the main part of the Earth upper mantle. In a second part, using this methodology we show that microstructural features such as small grain sizes and preferential grain orientations can localize strain at the same intensity and can act together to produce an even stronger strain localization.

We imaged some structures related to a major fault plane which have not been illuminated by a previously conducted 3D active seismic survey due to their large dip angles. The imaging procedure is conducted by using microearthquakes as seismic sources.

The insights of this study will help to better understand how to identify basement linear structures and how these lineaments could be related to surface lineaments or geology in the context of the Central Gawler Craton, and to provide better targeting of surface areas to detect subsurface mineral systems in this region.

In weakly seismic or poorly monitored areas, the uncritical use of earthquake catalogues can be misleading. This is the case of a central sector in the Po Valley, where Northern Apennine and Southern Alps collide. We collect and reprocess the available instrumental data of about 300 earthquakes from 1951 to 2019. The seismicity is weak and deeper than expected, and far from some existing human activities carried on in the underground. The potential tectonic causative sources are still unknown.

Sensing the Earth is a fundamental operation for the future where geo-resources, like geothermal energy and CO₂ underground storage, will become important tools for addressing societal challenges. The development of networks of optical fibre cables give possibility of a sensing grid with an unprecedented spatial coverage. Here we investigate the potential of using portions of a optical fibre cable as a a standard seismometer for exploring the subsurface and monitoring the geo-resources.

Geological interpretations based on seismic depth images depend on an accurate subsurface velocity model. Reflection tomography is one method to iteratively update a velocity model based on depth error analysis. We used a warping method to estimate closely spaced data-driven depth error displacement fields. The application to a multichannel seismic line across the Sunda subduction zone illustrates the approach which leads to more accurate images of complex geological structures.

A large amount of new seismic data from the greater Alpine area have been obtained within the AlpArray and SWATH-D projects. S-to P converted seismic phases from the Moho and from the mantle lithosphere have been processed with a newly developed method. Examples of new observations are a rapid change in Moho depth at 13° E below the Tauern Window from 60 km in the west to 40 km in the east and a second Moho trough along the boundary of the Bohemian Massif towards the Western Carpathians.

By making a change to the way we solve the flexure equation, that describes how the earth's outer layer bends when it is subjected to loading by ice sheets or mountains , we develop new ways of using an old method from geodynamics. This lets us study the earth's outer layer by measuring a parameter called the elastic thickness, effectively how stiff and springy the outer layer is when it gets loaded, and and also how the earth's outer layer gets broken around its edges and in its interior.

Rocks in mountain belts have been deformed during continental collision causing a certain alignment of the minerals referred to as crystallographic preferred orientation (CPO). Minerals have anisotropic properties: the velocity of seismic waves, travelling through them is direction dependent. This leads to anisotropy of the rocks. We measured the CPO of common rocks within the Alps. With this data and know anisotropic properties of the minerals we calculated the seismic anisotropy of the rocks.

The localisation of an earthquake is affected by many uncertainties. To correctly propagate these uncertainties into an estimate of the earthquake coordinates and their associated errors, many simulations of seismic waves are needed. This operation is computationally very intensive, hindering the feasibility of this approach. In this paper, we present a series of deep learning methods to produce accurate seismic traces in a fraction of the time needed with standard methods.

We combine gravity anomaly and topographic data with observations from thermochronology, metamorphic grades, and the granite inventory to detect patterns of basement block segmentation and differential uplift along the southwestern Bohemian Massif. Based on our analyses, we introduce a previously unknown tectonic structure termed Cham Fault, which, together with the Pfahl and Danube shear zones, is responsible for the exposure of different crustal levels during late to post-Variscan times.

Generating an accurate model of the subsurface is crucial when assessing a site for CO₂ storage, particularly for a fault bound storage site that may act as a seal or could reactivate upon CO₂ injection. However, we have shown how picking strategy, i.e. line spacing, chosen to create the model significantly influences any subsequent fault analyses, but is surprisingly rarely discussed. This analysis has been performed on the Vette Fault bounding the Smeaheia potential CO₂ storage site.