Antoine Lucas

Institut de Physique du Globe de Paris
Planetary and Space Sciences group
External envelopes geochemistry group

CNRS research scientist

About me

My research is focused on understanding the evolution of surfaces and near surfaces of the Earth and other planets, including lakes on Titan, landslides on Mars and icy satellites as well as aeolian transport on Mars, Venus and Titan. Other planets allow us to test our understanding of geological and climate processes under a wide range of conditions. By combining observations from planetary exploration missions with image processing and numerical modeling, I try to understand what controls the evolution of continental surfaces (including planetary counterparts) and more specifically mass wasting (landslides, avalanches, debris flows…), aeolian and hydrology processes. I defined mysleft as a space-hacker, an astro-geologist, a landscape-analyst and a space avalancher.

Along with my scientific activites, I am also in charge of the Natural Hazard master program at IPGP since 2023.

Recent Publications

A rockslide-generated tsunami in a Greenland fjord rang Earth for 9 days

Kristian Svennevig, Stephen P. Hicks, Thomas Forbriger, Thomas Lecocq, Rudolf Widmer-Schnidrig, Anne Mangeney, Clément Hibert, Niels J. Korsgaard, Antoine Lucas, Claudio Satriano, Robert E. Anthony, Aurélien Mordret, Sven Schippkus, Søren Rysgaard, Wieter Boone, and 53 more authors

Science, 2024.

abstract PDF url

Climate change is increasingly predisposing polar regions to large landslides. Tsunamigenic landslides have occurred recently in Greenland (Kalaallit Nunaat), but none have been reported from the eastern fjords. In September 2023, we detected the start of a 9-day-long, global 10.88-millihertz (92-second) monochromatic very-long-period (VLP) seismic signal, originating from East Greenland. In this study, we demonstrate how this event started with a glacial thinning–induced rock-ice avalanche of 25 × 10^6 cubic meters plunging into Dickson Fjord, triggering a 200-meter-high tsunami. Simulations show that the tsunami stabilized into a 7-meter-high long-duration seiche with a frequency (11.45 millihertz) and slow amplitude decay that were nearly identical to the seismic signal. An oscillating, fjord-transverse single force with a maximum amplitude of 5 × 10^11 newtons reproduced the seismic amplitudes and their radiation pattern relative to the fjord, demonstrating how a seiche directly caused the 9-day-long seismic signal. Our findings highlight how climate change is causing cascading, hazardous feedbacks between the cryosphere, hydrosphere, and lithosphere.
Possibly seismically triggered avalanches after the S1222a Marsquake and S1000a impact event

A. Lucas, I.J. Daubar, M. Le Teuff, Clement Perrin, T. Kawamura, L. Posiolova, P. Lognonné, S. Rodriguez, D. Giardini, G. Sainton, A. Mangeney, and A. Mcewen

Icarus, 2024.

abstract PDF url

Ground motion from seismic events detected by the SEIS/InSight seismometer on Mars could potentially trigger dust avalanches. Our research strongly suggests that the seismic event S1000a may have triggered a significant number of dust avalanches. In contrast, following the seismic event S1222a, there was only a modest increase in avalanche occurrences. Orbital observations of the area surrounding the projected location of the S1222a quake reveal notable topographic features, such as North-South ridges and impact craters. We utilize orbital imagery to evaluate the rate of avalanches and explore how the S1222a event might have influenced this rate. The S1222a event appears to be a plausible factor contributing to the observed increase in avalanches. Our further analysis of the epicenter location aims to clarify how it aligns with the avalanches’ spatial distribution, offering insights into the regional topography.
The 1965 Mahavel Landslide (Réunion Island, Indian Ocean): Morphology, Volumes, Flow Dynamics, and Causes of a Rock Avalanche in Tropical Setting

Laurent Michon, Eric Gayer, Antoine Lucas, Franziska Bellin, and Matthieu Gougeon

Journal of Geophysical Research: Earth Surface, 2023.

abstract PDF url

In May 1965, a main landslide occurred in a deeply incised valley of Piton de la Fournaise volcano, in Réunion Island. This event occurred one day after heavy rainfalls and was consequently interpreted as a mud/debris flow. We take advantage of several sets of historical photographs to reappraise this event. They show that the collapse of a large part of the valley headwall produced a rock flow that dropped 1,740 m and traveled 5,050 m. The surface morphology suggests that the landslide produced a main flow that evolved in a secondary flow in the distal part. The main flow deposit is composed of a matrix-rich fragmented facies and a jigsaw-fracturated facies. The matrix presents a gravely-to-silty granulometry and fractal dimensions ranging between 2.472 and 2.865. Volumes of the collapsed material (59.7 ± 3.1 Mm3) and the deposit (46 ± 13 Mm3) were determined from a photogrammetric approach. We estimated velocities ranging between 86 and 44 m s−1 along the flow path. Our simulations with SHALTOP reveal that the landslide geometry and velocities are well reproduced with frictional Coulomb rheology. We thus interpret the 1965 Mahavel landslide as a main rock avalanche rather than a mud/debris flow. We propose that the trigger of the 1965 avalanche, and of the smaller events in 1995 and 2001, is the water infiltration related to the intense rainfalls, which systematically preceded by one day each collapse. Finally, the succession of dry and wet years before each collapse event could promote favorable conditions to failure.
Phenomenological model of suspended sediment transport in a small catchment

Amande Roque-Bernard, Antoine Lucas, Eric Gayer, Pascal Allemand, Céline Dessert, and Eric Lajeunesse

Earth Surface Dynamics, 2023.

abstract PDF url

We develop a phenomenological model of suspended sediment transport on the basis of data acquired in the Capesterre river, which drains a small tropical catchment in Guadeloupe. The model correctly represents the concentration of suspended sediment during floods, provided that the relation between concentration and water level forms a counterclockwise loop. In the model, the properties of the sediment and of the river are all lumped into four parameters: a settling velocity related to the size of the suspended sediment, a threshold water level which acts as a proxy for the threshold shear stress, a characteristic entrainment rate, and a dimensionless exponent. The value of the parameters changes from one flood to the next, probably reflecting changes in the characteristics of the river and the fine sediment. Finally, a test of the model against data acquired in a small catchment in the French Alps suggests that the model is versatile enough to be used in diverse hydrological settings.