Publications associées à Rock strength properties of granitic rocks in Yosemite Valley, Yosemite National Park, California

Overview of the Alaskan Layered Pollution and Chemical Analysis (ALPACA) Field Experiment

Athanasios Nenes, Julia Schmale, Andrea Baccarini, Roman Pohorsky, Sukriti Kapur

The Alaskan Layered Pollution And Chemical Analysis (ALPACA) field experiment was a collaborative study designed to improve understanding of pollution sources and chemical processes during winter (cold climate and low-photochemical activity), to investigat ...

2024

Fluid flow through microcracked and fractured granitic reservoirs

Marie Estelle Solange Violay, Lucille Jocelyne Nadine Carbillet, Michael Heap

The permeability of crustal rocks and rock-masses dictates the efficiency of hydrothermal circulation and therefore the productivity of geothermal resources. In this study, we find by monitoring P-wave velocity that thermal microcracking in Lanhélin granit ...

2023

Reactivation of variably sealed joints and permeability enhancement in geothermal reservoir rocks

Alexandra Roma Larisa Kushnir, Michael Heap

Hydraulic stimulation of enhanced deep geothermal reservoirs commonly targets pre-existing joint networks with the goal of increasing reservoir permeability. Here, we study the permeability and strength of joint-free and jointed Buntsandstein sandstones fr ...

2023

Elongated hydraulic fracture emerging from layers of alternating fracture toughness

Brice Tanguy Alphonse Lecampion, Carlo Peruzzo

Whether used to enhance the hydrocarbon production from low permeability rocks or to measure the minimum in-situ principal stress in rock formations, height growth of a hydraulic fracture above the formation of interest is a key metric for the design of su ...

2023

Physical characterization of fault rocks within the Opalinus Clay formation

Marie Estelle Solange Violay, Luis Felipe Orellana Espinoza, Christophe Nussbaum

Near-surface disposal of radioactive waste in shales is a promising option to safeguard the population and environment. However, natural faults intersecting these geological formations can potentially affect the long-term isolation of the repositories. Thi ...

Nature Research2022

Experimental plastic reactivation of pseudotachylyte‐filled shear zones

Marie Estelle Solange Violay, François Xavier Thibault Passelègue

Pseudotachylytes are fine‐grained fault rocks that solidify from melt that is produced in fault zones during earthquakes. Exposed sections of natural fault zones reveal evidence of post‐seismic plastic deformation (i.e. reactivation) of pseudotachylyte, wh ...

2021

A new data set of granitic rock strength values from Yosemite Valley, California: applications to rock fall assessment

To explore connections between rock strength and rock falls, we undertook a comprehensive rock mechanics testing program for six granitic rock types in Yosemite Valley (California, USA) where rock falls are a common geomorphic and sometimes hazardous proce ...

2020

Hydraulic stimulation of pre-existing discontinuities in tight rocks

Federico Ciardo

Hydraulic stimulation is an engineering technique whose aim is to enhance the permeability of fractured rock masses at depths ranging from one to five kilometers. It consists in the injection of fluid at sufficiently high pressure in order to shear pre-exi ...

EPFL2020

Evidence of extensive lunar crust formation in impact melt sheets 4,330 Myr ago

Cyril Cayron

Accurately constraining the formation and evolution of the lunar magnesian suite is key to understanding the earliest periods of magmatic crustal building that followed accretion and primordial differentiation of the Moon. However, the origin and evolution ...

2020

Mountain snow: The source of the mother river—Study of multi-scale and multi-physical process of spatio-temporal evolution of snow distribution

Guang Li

Snow is one of the most active elements on the earth, which is an important mass source of polar ice sheets and alpine glaciers, as well as a main supply for the runoff. Its distribution and evolution have a great impact on global hydrological cycle, ecosy ...

2020