INFRASTRUCTURE

Laboratory Facilities and Experimental Devices

The LMA technical equipments consist of about a dozen motorized and computerized experimental devices designed to conduct 2D and 3D analog modeling experiments. They are installed in two main experimentation rooms. Other dedicated spaces are used to store, prepare and analyze the analog materials.

Experimentation Room 1

This room is equipped with several experimental setups. A lab-made multi-purpose direct shear box device for measuring the mechanical properties of dry or wet granular materials (cohesion, internal friction), elastomer, and PU/PE foams (Young/shear modulus, Poisson’s ratio). This system is completed with a Brookfield viscosimeter to measure the viscosity of ductile analog materials such as PDMS silicone compounds, glycerol, etc. A large 3D shear-box device (1m x 0.8m) allows for performing strike-slip fault experiments. This device is also equipped with a motorized backstop to perform extensional experiments. Two long experimental set-ups (>2m) are dedicated to the study of crustal deformation in 2D (cross-section). They can be used to investigate orogenic prism formation, tectonic inversion processes, crustal extension, subduction zone seismic cycle, and many more geological processes. Two short (<1m) 2D devices are used to conduct preliminary tests.

Some views of the experimentation room1

Experimentation Room 2

This room is mainly dedicated to performing large 3D analog modeling experiments. It is equipped with three 3D tables (very large, large, and medium) and 2D subduction-type devices. Two rainfall systems, a laser interferometer, and two photogrammetric monitoring devices complement the experimental setups.

Some views of the experimentation room 2

Technics

Most, if not all, experimental setups and monitoring devices are designed and built in-house through a close collaboration between the scientific and technical lab managers (S. Dominguez and C. Romano). The LMA also benefits from the facilities of the technical platform of the Geosciences Montpellier lab. (managed by J. Oustry and Sylvain Royer). The electronic assemblies and computer programming, required to control the sensors and the motors, maintenance, and repair are carried out internally by the LMA managers.

Some examples of lab-(Christian)-made mechanical devices and experimental setups

Monitoring

The metrology equipments include; a laser interferometer to digitize the model topography and create sub-millimeter resolution DEMs, several optical digital measuring benches (digital cameras) to record experiment evolution and quantify model topography, and deformation, using image analysis algorithms (photogrammetry, laser interferometry, sub-pixel correlation). And a recently purchased 3D scanner (Einscan HX). Several other sensors (force, vibration, pressure, laser, etc.) complement these devices.

Examples of technical devices used to monitor and quantify analog model evolutions (Laser interferometry, Photogrammetry, Digital Model Elevation, Laser scanner, etc.)