Recent  

Mantle rocks can bind large quantities of carbon by reaction with CO₂, but this capacity requires that fluid pathways are not clogged by carbonate. We studied mantle rocks from Oman to understand the mechanisms allowing their reaction to carbonate and quartz. Using advanced imaging techniques, we show that abundant fractures were essential fluid pathways driving the reaction. Our results show that tectonic stress was important for fracture opening and a key ingredient for carbon fixation.

The Earth’s surface deforms due to surface mass load such as ice sheets and subsurface dynamics. Sea level and GPS data show North America (NA) is undergoing surface deformation, due to past ice loads and/or Earth’s interior pull by dense material. We employ mathematical methods and computer simulations to study the region viscosity/strength as a function of depth using a localization technique. Our results show the east of NA has a stiff interface compared to the western part.

Fluid flow through rock occurs in many geological settings on different scales, at different temperature conditions and with different flow velocities. Fluid is eitherin local thermal equilibrium with the host rock or not. We explore the parameters of porous flow and give scaling laws. These allow to decide whether porous flows are in thermal equilibrium or not. Applied to magmatic systems moving melts in channels or dyke moderately to strongly deviate from thermal equilibrium, respectively.

Earthquake extent prediction is limited by our poor understanding of slip deficit patterns. From a mechanical analysis applied along the Chilean margin, we show that earthquakes are bounded by extensive plate interface deformation. This deformation promotes stress build-up leading to earthquake nucleation, earthquakes then propagate along smoothed fault planes, and are stopped by heterogeneously distributed deformation. Slip deficit patterns reflect the spatial distribution of this deformation.

Glacial Isostatic Adjustment is considered as a major process of seismicity in intraplate regions such as Scandinavia and eastern North America. We show that GIA associated with the alpine icecap induces a present-day response in vertical motion and horizontal deformation seen in GNSS strain rate field. We show that GIA induced stress is opposite to strain rate, with the paradoxical consequence that postglacial rebound in the Western Alps can explain the strain rate field but not the seismicity.

In passive seismic measurement, all noise sources from environment, such as traffic, vibrations caused by distant excavation and explosive work from underground mine are utilized. In the Kylylahti experiment, receivers were recording ambient noise (AN) sources for 30 days. These recordings were subjected to data analysis and processing using novel methodology developed in our study and used for imaging of the subsurface geology of the Kylylahti mine area.

Several alternative gravity modelling techniques and associated numerical codes with their own advantages and limitations are available for the Solid Earth community. With the upcoming state-of-the-art lithosphere density models and accurate global gravity field data sets it is vital to understand the differences of the various approaches. In this paper, we discuss the four widely used techniques: spherical harmonics, tesseroid integration, triangle integration, and hexahedral integration.

Underground energy and waste storage require re-purposing of existing oil and gas wells for gas storage; compressed air, hydrogen, methane and CO₂ disposal, requiring an impermeable cap rock (e.g. shales) over the porous reservoir. We measured shale permeability over a range of burial pressures and gas pore pressures. Permeability decreases markedly as effective pressure on the rocks is increased. Knowing these relationships is essential to the safe design of engineered gas reservoirs.