This paper investigates the numerical age of the J–K boundary that remains one of the last main Phanerozoic system boundaries without an adequate constraint by adequate radioisotopic ages. Here we find that there is potentially 4 Myr of difference between the current age of the J–K boundary and our data.

Successive earthquakes on a single fault are not perfectly periodic in time. There is some natural random variability. This leads to variations in estimated fault slip rates over short timescales though the longer-term mean slip rate stays constant, which may cause problems when comparing slip rates at different timescales. This paper is the first to quantify these effects, demonstrating substantial variation in slip rates over a few to tens of earthquakes, but much less at longer timescales.

This work attempts to create a semi-automated algorithm (called SPARTA) to calculate height, width and slope of surface breaks produced by earthquakes on faults. We developed the Python algorithm using synthetic catalogues, which can include noise features such as vegetation, hills and ditches, which mimic natural environments. We then apply the algorithm to four fault scarps in southern Malawi, at the southern end of the East African Rift system, to understand their earthquake potential.

On 3 September 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.

Vast amounts of methane are released to the oceans at continental margins (seepage). The mechanisms controlling when and how much methane is released are not fully understood. In the Fram Strait seepage may be affected by complex tectonic processes. We modelled the stress generated on the sediments exclusively due to the opening of the mid-ocean ridges and found that changes in the stress field may be controlling when and where seepage occurs, which has implications for seepage reconstruction.

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 and dislocation glide, followed by growth and granular flow.

The Caledonian mountains formed when Baltica and Laurentia collided around 450–400 million years ago. This work describes the history of the rocks and the dynamics of that continental collision through space and time using field mapping, estimated pressures and temperatures, and age dating on rocks from northern Norway. The rocks preserve continental collision between 440–430 million years ago, and an unusual pressure–temperature evolution suggests unusual tectonic activity prior to collision.

The Mesozoic sequences of the Oman mountains experienced only weak post-obduction overprint and deformation, and thus they offer a unique natural laboratory to study obduction. We present a study of pressure and temperature evolution in the passive continental margin under the Oman Ophiolite using numerical basin models calibrated with thermal maturity data, fluid-inclusion thermometry, and low-temperature thermochronology.

A detailed knowledge of the very shallow subsurface has become of crucial interest for 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, based on the 3-D distribution of seismic velocities and well-log data, which are of great interest for 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 idealized case and apply it to the Yerrida Basin (Australia), where we can recover the geometry of buried greenstone belts.

This geochronological and thermometric study reveals unusually hot fluids in an Alpine-type fissure of granite from the external crystalline massif (Western Alps). The fluid is estimated to be 150-250 °C hotter than the host rock and requires a dynamic fluid pathway at mid-crustal conditions in the ductile regime. This fluid circulation resets the zircon fission track thermochronometer, but only at the fissure contact. Thermal disturbances due to advective heating appear to be localized.

Plate-scale rifting is frequently expressed by the subsidence of structural basins along an axis, but postdating tectonic and magmatic activity mostly obscures them. A 3-D subsurface imaging and facies analysis down to 1 km reveals 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), prevents them from dying out peacefully.

Granite is suitable to host geothermal wells or disposals of hazardous waste and in these cases the rock porosity and permeability are critical. Our detailed porosity and permeability data on variously deformed Lipnice granite yield a span of 5 orders of magnitude in permeability between the least and the most deformed facies. To facilitate the estimation of porosity and permeability in similar settings, we provide optical and chemical data on the characteristic minerals of each facies.

Recent seismological observations clarified that the velocity structure of the crust and upper mantle is randomly heterogeneous. I compile reported power spectral density functions of random velocity fluctuations based on various types of measurements. Their spectral envelope is approximated by the third power of wavenumber. It is interesting to study what kinds of geophysical processes created such a power-law spectral envelope at different scales and in different geological environments.

A terrestrial reference frame (TRF) realization is a basis for precise orbit determination of Earth-orbiting artificial satellites and sea level studies. We investigate the impact of a switch from an older TRF realization (ITRF2008) to a new one (ITRF2014) on the quality of orbits of three altimetry satellites (TOPEX/Poseidon, Jason-1, and Jason-2) for 1992–2015, but especially from 2009 onwards, and on altimetry products computed using the satellite orbits derived using ITRF2014.

Calcite twinning is a common deformation mechanism that mainly occurs at low temperatures. Twinning activation appears at a critical strength value, which is poorly documented and still debated. Temperature is known to influence twin thickness and shape; however, few studies have been conducted on calcite deformation at low temperatures. The goal of this work is to determine if thickness is mainly due to high temperatures and to establish the validity of a threshold twinning activation value.

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 thousands of earthquakes are registered within a few days. We find reduced attenuation within the active volume, which may indicate high fluid content.

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.

Physical properties of layered sedimentary rocks affect nucleation and propagation of discontinuities therein. Fractures developing through sedimentary sequences characterized by the alternation of strong and weak layers are strongly deviated along their track at layers’ boundaries, and depending on the layer they cross-cut, they show very thick (strong layers) or very thin (weak layers) infills of precipitated minerals, potentially representing pathways for ore deposits and oil/water resources.

The channel flow model proposed by Marques et al (2018) for the Himalayas has a geometry that would not generate any excess pressure. The excess pressure calculated by the authors, based on a different and highly improbable geometry, is so high that the overlying rocks would not be able to contain it: they would bend or break in such a way as to relieve the pressure. The conclusions drawn by the authors are therefore unwarranted and misleading.