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. A geomorphologist by objects of study, a geophysicist by methods, and a planetary scientist by perspective; 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/Université Paris Cité since 2023.

Recent Publications

Unveiling tropical slow-moving landslides response to seasonality and extreme meteorological events using a combination of InSAR and optical imagery: the case study of Grand Eboulis (Réunion island)

Coline Hopquin, Eric Gayer, Laurent Michon, Antoine Lucas, Delphine Smittarello, Nicolas d’Oreye, and Nicolas Villeneuve

Geomorphology, 2025.

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Slow-moving landslides can cause significant infrastructure damage and casualties, making their monitoring a critical societal challenge. In the context of climate change and the projected intensification of rainfall extremes, understanding the response of slow-moving landslides to extreme meteorological conditions is essential. However, ground-based surveys are often difficult. In this study, we associate radar interferometry and optical imagery to investigate the dynamics of a remote tropical slow-moving landslide on Réunion Island, Grand Eboulis, and its relationship with precipitation regimes. Our approach enables us to retrieve (1) the bi-monthly dynamics of the Grand Eboulis landslide from cumulative displacement maps and ground deformation time series derived from Sentinel-1B images and (2) its multi-annual dynamics from optical aerial images. Between 2016 and 2021, the landslide moved eastward and downward at rates of up to 14 cm/yr and 9 cm/yr, respectively. Displacement was punctuated by periods of accelerated motion following an exceptionally wet season in mid-2018. In contrast, two slower periods coincided with the 2018 dry season combined with an exceptionally arid 2019, and with a prolonged drought in 2020. Additionally, between 2017 and 2019, shallow failures were mapped only in 2018 at the landslide front and were attributed to Cyclone Dumazile. This study suggests that slow-moving landslides may respond to seasonal contrasts by modulating their continuous displacement and to extreme events through shallow failures. The combined use of InSAR and remote sensed optical imagery proved to be efficient for studying such a type of events and can easily be widely applicable.
Evidence for Erosional Efficiency of Extreme Precipitation Events at a Multi-Decadal Time Scale

E. Gayer, A. Lucas, L. Michon, and M. Gougeon

Journal of Geophysical Research - Earth Surface, 2025.

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Extreme precipitation events play a pivotal role in shaping Earth’s surface through their influences on hillslope processes (triggering mass-wasting events) and on transport capacity and dynamics of rivers. This study investigates the impact of such events on sediment transport using Réunion Island as a natural laboratory due to its intense tropical rainfall regime. Through photogrammetric techniques using historical aerial images, we reconstructed nine DEMs of the entire canyon bed of the ephemeral Rivière des Remparts spanning six decades. Based on differences in DEMs and sediment volume estimates combined with cosmogenic 3 He measurements, we assessed the spatio-temporal evolution of the entire canyon bed and the drainage of products from major landslides and rock avalanches between 1950 and 2011. Results indicate that 50.2 ± 8.4 Mm 3 (145.5 ± 24.4 Mt) of sediment was transported out of the watershed over 62 years via bed load waves. We modeled the flow dates and showed that such an export of material occurred during only 391 days over the 62 years, at an average rate of 0.13 ± 0.02 Mm 3 /day (0.37 ± 0.06 Mt/day). Our investigation confirms that sediment transport coincides with officially recorded extreme meteorological events such as cyclones. Moreover, our findings reveal that sediment transport predominantly occurs on days corresponding to highpercentile rank precipitation events, demonstrating that all transport is concentrated during these intense rainfall periods. Finally, we underscore the extremely fast conveyance of material from slopes to deep-sea fans, facilitated in Réunion by the absence of a coastal platform.
Mapping the surface characteristics of the Asal-Ghoubbet rift by massive inversion of the Hapke model on Pleiades multiangular images

D.T. Nguyen, S Jacquemoud, A. Lucas, S. Douté, C. Ferrari, S. Coustance, S. Marcq, and A. Meygret

Remote Sensing of Environment, 2025.

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A massive inversion of the Hapke model is carried out over the Asal-Ghoubbet rift (Republic of Djibouti) using high-resolution multiangular Pleiades images. This is the first time that such an inversion is performed on Earth over an entire image, previous studies having focused on planetary surfaces. This work addresses challenges such as atmospheric and geometrical corrections of these images to produce parameter maps. The use of fast Bayesian inversion significantly reduces computation times thanks to efficient exploration of the parameter space and leads to improved prediction. The parameters of the Hapke model are also interpreted in terms of surface physical properties, thanks to field measurements. Single scattering albedo is the parameter extracted with the greatest reliability, although its validation is still difficult due to the absence of a simple formula linking it to surface reflectance. Our study reveals a close relationship between photometric roughness and single scattering albedo, indicating that accurate extraction of the former is highly dependent on values of the latter, which must be below 0.8 for reliable estimation. Finally, the correlation between phase function parameters and grain properties depends on surface type and material properties.
Inferring discharge from river geometry on Titan

C. Daudon, S. Rodriguez, E. Lajeunesse, A. Lucas, and S. Jacquemoud

Geophysical Research Letters, 2025.

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Titan’s dense atmosphere, composed mainly of methane and nitrogen, maintains a methane cycle that shapes its surface. Like water on Earth, methane precipitation erodes Titan’s surface, carving river networks at all latitudes, as revealed by the Cassini-Huygens mission. On Earth, it is well known that laboratory and natural rivers exhibit a power-law relationship between their bankfull geometry and water discharge, as described by the threshold theory. Here, we investigate this hydraulic-geometric relationship on two rivers on Titan, one near the equator and the other at the south pole. We hypothesize that this relationship can be applied to any river, and test it for the first time on extraterrestrial rivers. Having shown that Titan’s rivers are consistent with the threshold theory, we use this relationship to estimate river discharge from bankfull geometry. As a perspective, we then use these discharges to infer precipitation rates, which could help to better understand Titan’s climate.