Objectives: 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.

Environment: The Doctoral Network “Studying the Earth’s surface with seismic methods” (EnvSeis) is funded by the European Commission’s Marie Skłodowska-Curie Actions. Bringing together 10 leading research groups from 7 countries, EnvSeis supports 12 early stage researchers in the emerging field of environmental seismology, in which seismic methods are used to study processes at or near the Earth's surface, such as landsliding, river sediment transport, debris flows, and glacial processes. Projects in the network are connected by the common methodology and joined training and networking activities. The PhD will work in ISTerre Grenoble, in the “fault mechanics” team. The research team will also include the Geo3iLab LabCom (public/private joint laboratory with Geolithe Company, Crolles).

Candidate background: Master in physics, mechanics, acoustics, geophysics

Additional optional skills: experience in field work, alpine and vertical environments, numerical simulations