INFRASTRUCTURE

Laboratory Facilities and Experimental Devices

The LMA’s technical infrastructure comprises a dozen motorized and computer-controlled experimental apparatuses dedicated to 2D and 3D analogue modeling. These systems are installed across two primary experimental halls optimized for controlled deformation experiments. Additional dedicated facilities are allocated to the storage, preparation, conditioning, and post-experimental analysis of analogue materials.

---

Experimentation Room 1

This room hosts a suite of experimental setups dedicated to analogue tectonic modeling. It includes a custom-built, multi-purpose direct shear apparatus for the quantitative characterization of the mechanical properties of dry and wet granular materials (cohesion and internal friction), elastomeric materials, and PU/PE foams (Young’s modulus, shear modulus, and Poisson’s ratio). This system is complemented by a rotational rheometer (Brookfield) used to determine the viscosity of ductile analogue materials such as PDMS silicone compounds or glycerol. A large three-dimensional shear-box apparatus (1 m × 0.8 m) is dedicated to strike-slip fault modeling and is equipped with a computer-controlled motorized backstop, enabling both strike-slip and extensional deformation experiments. Two long two-dimensional analogue modeling rigs (>2 m) are dedicated to cross-sectional crustal-scale deformation experiments, allowing investigation of processes such as orogenic wedge development, tectonic inversion, lithospheric extension, and subduction-zone seismic cycle processes. Two shorter 2D rigs (<1 m) are used for pilot, calibration, and feasibility experiments.

Some views of the experimentation room1

---

Experimentation Room 2

This room is primarily dedicated to large-scale three-dimensional analogue tectonic modeling experiments. It is equipped with three experimental tables of different dimensions (very large, large, and medium) and two-dimensional subduction-type analogue modeling devices. The experimental infrastructure is complemented by three automated rainfall erosion systems, a high-precision 3D laser scanner for quantitative monitoring of model topography evolution, and two photogrammetric monitoring systems based on very-high-resolution cameras, for continuous three-dimensional surface deformation analysis. These capabilities enable systematic, reproducible investigations of complex tectonic processes at laboratory scale, consistent with best practices in international analogue modeling laboratories.

Some views of the experimentation room 2

---

Technics

Most, if not all, experimental setups and monitoring systems have been designed and fabricated in-house through close collaboration between the scientific and technical laboratory managers (S. Dominguez and C. Romano, now retired). The LMA also leverages the resources of the Geosciences Montpellier technical platform (managed by S. Royer). All electronic assemblies, sensor and motor control programming, maintenance, and repair are performed internally by the LMA team (including now O. Maudens), ensuring full integration, high reliability, and rapid adaptability of the experimental infrastructure.

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.)

---