Sismo-Acoustic monitoring of rock erosion

surveillance sismo-acoustique de l’érosion des roches

• Contexte du stage : rock damage is a key to erosion of mountainous landforms, but also is a major source of natural hazard and risk. Erosion is mostly due to cumulative damage, related to tectonic forcing on the large scale, but also on thermal cycles (including freezing) and water dissolution on a smaller scale. The role of stress changes induced by changes of outside temperature and/or solar radiation has been subject to limited attention and little quantitative measurements. Thanks to a novel approach to quantify stress changes in the bulk of the rock, using sonic and ultrasonic techniques, we will investigate the role of thermal cycles and environmental forcings on progressive damage of rocks on cliffs.

• Objectifs du stage : The goal is to quantify erosion and damage (opening of small fractures) in natural rocks due to daily thermal cycles (and possibly freezing), in relation to the solar radiation and outside air temperature fluctuations. To that end, we will perform laboratory and field measurements, to observe relative seismic/acoustic velocity changes, stress changes, surface temperature and solar radiation changes, and identify possible correlations between those physical data.

• Points-forts : joint laboratory between ISTerre and the Geolithe Company ; field experiments ;

• Pour postuler : send your CV and marks (licence and master) to eric.larose univ-grenoble-alpes.fr

• Références bibliographiques : E. Larose, S. Carrière, C. Voisin, P. Bottelin, L. Baillet, P. Guéguen, F. Walter, D. Jongmans, B. Guillier, S. Garambois, F. Gimbert, C. Massey : Environmental seismology : what can we learn from ambient seismic noise ?, J. Appl. Gephys., 116, 62-74,(2015).