Offre de thèse : Acoustic and Seismic of natural cliffs, to better understand and monitor fracturation and erosion process.

Présentation de la structure

The Institut des Sciences de la Terre (ISTerre) is an academic laboratory under the supervision of the CNRS, the IRD, the University of Grenoble Alpes (UGA) and Grenoble-INP, which works on geology, geochemistry, geophysics and all internal earth sciences, the anthropization of our planet and other planets of the solar system.

It brings together around 300 people, including more than 150 permanent members (researchers, teacher-researchers, engineers and technicians) and around 100 staff on fixed-term contracts (doctoral students, researchers and IT). The laboratory also welcomes dozens of interns and visiting scientists every year. The laboratory is located on two sites, on the Grenoble university campus (OSUG C building) and on the Chambéry – Le Bourget du Lac campus.

ISTerre is one of the main laboratories of the Observatory of Sciences of the Universe of Grenoble (OSUG), a federative structure of INSU.

Missions principales

The recruited person will carry out his PhD within the Faille team and will be placed under the responsibility of Eric LAROSE, CNRS Research Director at ISTerre.

In collaboration with Laurent BAILLET, UGA Professor at ISTerre. The team is composed of about 10 persons.

Activités principales

In the phase preceding catastrophic slope failure, rocks are progressively damaged and fractured. To quantify and image the damage and fracturing process in natural rock cliffs and slopes, two experiments will be performed. 1) a rock column will be equipped with seismic, geodetic and meteorological sensors 2) a rock slop (cliff) will be equipped with sonic sensors together with environmental (meteorological/solar radiation) sensors. The goal will be to determine how the change of natural resonance (rock column) or the change of sonic velocity change and decorrelation (rock cliff) are affected by ambient meteorological conditions, revealing onsite the intimate and slow damage processes due to environmental forcings. These experiments will be combined with numerical transient-thermo-elastic simulations. The project will explore instrumentation and methods to differentiate irreversible damage and fracturing and seasonal, reversible effects, and to track the evolution of damage. Using ambient seismic noise cross-correlation, structural changes in rock mass will be detected while stress changes and fracture development will be tracked with active coda waves (acoustic probing). Both approaches will be performed on various time scales, from daily (role of the local weather) to yearly (seasonal) timescales.

Expected results : The project will give quantitative insight into damage, fracturing and erosion processes in rock cliffs. It will distinguish between the role of stress cycles induced by thermo-elastic cycles from other erosive solicitations. Finally, it will identify a chronology of possible geophysical, meteorological and geodetic precursor signals to failure, which may enhance early warning systems.

Mobility requirement : the candidate should not have spent more than one month (1) in France over the last three (3) years.

Compétences attendues

• Skills in mechanics, physics, wave physics, acoustics, geophysics and seismology, signal processing...
• Good writing skills in English.
• Interest in carrying out laboratory experiments and work on the field.
• Demonstrate autonomy.
• Sense of organization.
• Ability to produce instrumental assemblies and ability to interact with technicians and engineers.
• Experience in field work, alpine and vertical environments, numerical simulations.
• Volunteer at work.
• Passionate.
• Desire to learn.
• Ability to question and to interact with people with varied sensitivities.

Bac +5 : Master in physics, mechanics, acoustics, geophysics

Conditions de diplômes

Bac + 5

Rémunération

A partir de 2832€ mensuel brut et en fonction de l’expérience.
Vous percevrez en plus de votre salaire un régime indemnitaire d’un montant mensuel brut de Possible travel expenses max 600€ gross per month €.

Pour toutes informations complémentaires

– Sur le recrutement
Sophie BARDIN, chargé.e de recrutement
sophie.bardin univ-grenoble-alpes.fr
– Sur le poste
Eric LAROSE, CNRS director researcher at the ISTerre, director of this thesis.
eric.larose univ-grenoble-alpes.fr