A large quantity a contiental material is transported to the oceans by the world rivers. Once in the ocean, these particles can be transported down the continental shelf thanks to underwater avalanches. The repetition of such massive events can form very important sedimentary deposits at the continent-ocean transition. Data obtained during an oceanic cruise in 2010 allowed us to study such a system located offshore Gabon and to evaluate the importance sediment transport in this area.

Natural fractures have a strong influence on fluid flow in subsurface reservoirs. Our research presents a new methodology to predict the arrangement of these fractures in rocks. Contrarily to the commonly-used statistical models, our approach integrates more geology in the simulation process. The method is simply based on drawing of images, can be applied to any type of rocks in various geological contexts and is suited for fracture network prediction in water, heat or hydrocarbon reservoirs.

The fall of the Dead Sea level since the 1960s has provoked rapid incision of stream channels and the formation of over 6000 sinkholes, a major hazard to local economy and infrastructure. In this context, we study the evolution of the Dead Sea’s eastern shore from 1967–2017. The study is the first to examine surface and subsurface hydrological response to lake level fall over such a timescale, and demonstrates how sinkhole development is spatio-temporally linked to the declining Dead Sea level.

We constructed a seismic velocity model of the North Anatolian Fault in Turkey. We found that the fault is located within a region of reduced seismic velocity, and skirts the edges of a geological unit that displays high seismic velocity, indicating that this unit could be stronger than the surrounding material. Furthermore, we found that seismic waves travel fastest in the NE–SW direction, which is the direction of maximum extension for this part of Turkey, and indicates mineral alignment.

This study aims to provide some advancements towards a quantitative understanding of the spatial/temporal evolution of chemical heterogeneities in the mantle. Several equilibration models between a peridotite-type and a gabbro-type sub-system have been performed and the results parameterized. The first application is a series of 1-D numerical models of two sub-systems assuming variable initial proportions. The second application considers 2-D models in which one of the two sub-systems is mobile.

We show the landslide response to the 2016 Kumamoto earthquake (M_W 7.1) in central Kyūshū (Japan). Landslides are concentrated to the northeast of the rupture, coinciding with the propagation direction of the earthquake. This azimuthal variation of the landslide concentration is linked to the seicmic rupture process itself and not to classical landslide susceptibility factors. We propose a new ground motion model that links the seismic radiation pattern with the landslide distribution.

Plate-scale rifting is frequently expressed by the subsidence of structural basins along an axis. Postdating tectonic and magmatic activity however, mostly obscure them. Our 3D subsurface imaging and facies analysis down to 1 km, reveal uniquely preserved Galilean basins subsiding along a failing rift front in two main stages. Rifting within a large releasing jog (20–9 Ma) followed by localized grabenization off the Dead Sea fault plate boundary (9–5 Ma), prevent them from dying out peacefully.

On September 3rd 2017 official channels of the Democratic People’s Republic of Korea announced the successful test of a nuclear device. This study provides a multi-technology analysis of the 2017 North Korean event and its aftermath using a wide array of geophysical methods (seismology, infrasound, remote sensing, radionuclide monitoring and atmospheric transport modeling). Our results clearly indicate that the September 2017 North Korean event was in fact a nuclear test.

On one of the least studied boundaries between tectonic plates, one which moves very similarly to the famous San Andreas fault in California, we have found the traces of earthquakes from the recent past, but before the time when human history could record them. What this means is that we are a little more sure that the fault is still the place where movement between the plates takes place, and when it happens again, there could be dangerous earthquakes.

The maximum earthquake magnitude is one of the fundamental parameters to assess possible threats on populations. Considering all mapped faults in Italy, empirical scaling laws between fault dimensions and earthquake magnitude are used at the national scale. Results are compared with earthquake catalogues. The consistency between our results and the catalogues gives credibility to the method. Some large differences between the two datasets suggest the validation of this experiment elsewhere.

The channel flow model proposed by Marques et al (2018) has a geometry that would allow any excess pressure to leak out downwards. The calculated values of excess pressure are so high that they would inflate the overlying rock layer like a balloon, largely relieving the pressure. If the excess pressure were maintained by continuing channel flow, the resulting topography would be several times higher than the present-day Himalayas.

We developed a method that allows to estimate the acoustic attenuation of seismic waves within regions with high earthquake source densities. Attenuation is of high interest as it allows to draw conclusions on the origin of seismic activity. We apply our method to North-West Bohemia which is regularly affected by earthquake swarms during which thousand of earthquakes are registered within few days. We find reduced attenuation within the active volume which may indicate high fluid content.

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 the our model results and the discussion on which specific tectonic settings they could represent may serve as a guide for future (analogue) modeling studies.

In order to assess the influence of deformational processes within accretionary prisms, we track the evolution of the energy budget. We track the consumption of energy stored in internal deformation of the host rock, energy expended in frictional slip, energy used in uplift against gravity, and the total energy input. We find that the energy used in internal deformation is < 1 % of the total, and that the energy expended in frictional slip is the largest portion of the budget.

This study reveals the existence of advecting heating due to hot fluid circulations in a Alpine cleft (open fissure partly filled by hydrothermal crystals) of the external crystalline massif in the Western Alps. The source of the fluid is estimated > 6 km deeper compared to the granitic host-rock. This fluid circulation locally impacts the thermal regime and resets the zircon fission track thermochronometer. It demonstrates the existence of very efficient fluid pathways at mid-crustal conditions.

Interest and demand for green-type energy usage and storage is growing worldwide. Among several, thermal energy storage that stores energy (excess heat or cold) in fluids is particularly appealing. For an up-scaling purpose, three seismic profiles were acquired within the Tornquist suture zone in southwest of Sweden and historical crustal-scale offshore BABEL lines revisited. A number of dykes have been imaged and implications for the storage and tectonic setting within the zone discussed.

We use statistical analyses of synthetic position time series to estimate the potential precision of GPS velocities. Regression tree analyses show that the main factors controlling the velocity precision are the duration of the series, the presence of offsets and the noise. Our analysis allows us to propose guidelines which can be applied to actual GPS data, that constrain the velocity accuracies.

The calcite twinning is a common deformation mechanism mainly occuring at low temperatures. Twinning activation appears at a critical strength value, poorly documented and still debated. The temperature is known to influence the twin thickness and shape. However, only few studies have been conducted calcite deformation at low temperatures. The goal of this study is to determine if the thickness is mainly due to the high temperatures and the realness of a threshold value for tinning activation.

This research is dedicated to the study of poorly understood coal-bearing Mississippian (ca. 360–325 Ma) sedimentary rocks in central Spitsbergen. Our results suggest that these rocks were deposited during a period of widespread extension involving multiple fault trends, including faults striking sub-parallel to the extension direction, while overlying Pennsylvanian (ca. 325–300 Ma) were deposited during extension localized along fewer larger faults.

A detailed knowledge of the very shallow subsurface has become of crucial interest for the modern society, especially if it hosts critical surface infrastructures such as temporary waste storage sites. The use of indirect methods to characterize the internal structure of the subsurface has been successfully applied providing valuable information about the 3D geometry of the shallow lithological boundaries which are of great interest for the civil engineering companies.

We propose the quantitative integration of geology and geophysics in an algorithm integrating the probability of observation of rocks with gravity data to improve subsurface imaging. This allows geophysical modelling to adjust models preferentially in the least certain areas while honouring geological information and geophysical data. We validate our algorithm using an idealised case and apply it to the Yerrida Basin (Australia), where we can recover the geometry of buried greenstone belts.

We used microscopy and electron backscatter diffraction to analyse the deformation behaviour of feldspar at greenschist facies conditions in mylonitic pegmatites of the Austroalpine basement. There are strong uncertainties about feldspar deformation, mainly because of the varying contributions of different deformation processes. We observed that deformation is mainly the result of coupled fracturing, dislocation glide, strain-induced grain boundary migration and subsequent granular flow.

Time Reverse Imaging is a method for localizing quasi-simultaneous or low-amplitude earthquakes. Numerous three-dimensional synthetic simulations were performed to discover the influence of station distributions, complex velocity models and high noise rates on the reliability of localizations. The obtained guidelines enable the estimation of success rates with an existing station setup and provide a basis for designing new arrays.