Imaging and monitoring of the subsurface

The theme "Imaging and monitoring of the subsurface" builds on the previous scientific project themes "High-resolution subsurface imaging" and "Differential monitoring methods for surveillance."
First, the continuation of research dedicated to imaging includes the development of:

• Inversion strategies (notably for reconstructing the mechanical parameters of the subsurface in on-shore and offshore environments or for inferring property gradients of surface concrete),
• Differential reconstruction approaches to track the evolution of a pathology (dike monitoring), the water content of the critical zone, or the mechanical aspects of the subsurface under stress, or defect imaging in cables,
• Methodology based on seismic wave field homogenization for detecting cavities in the subsurface or for mechanical characterization of subsurface materials reinforced by rigid inclusions.

Next, the necessary developments for refining monitoring methods will continue to focus on methodologies combining the design of embedded devices (e.g., optical fibers for ultrasound) with signal processing and measurements to derive observables comparable to those obtained more conventionally by surface ND techniques. In this context, there is a planned increase in the use of optical fibers, whether at the laboratory scale, civil engineering structures, or in natural subsurfaces.