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Introduction
I am a CNRS research scientist. I'm interested in landscape dynamics under various conditions, such as gravity and climate from Niger to Titan. Since recently, I mainly focus on erosion and weathering in tropical islands and alpine environment.
Find out more about myself at http://geophysx.org
ORCID: orcid.org/0000-0003-2192-4416
Additional affiliations
October 2017 - present
January 2017 - September 2017
January 2015 - December 2016
Education
September 2006 - March 2010
September 2005 - July 2006
September 2004 - July 2005
Publications
Publications (178)
One of the ultimate goals in landslide hazard assessment is to predict maximum landslide extension and velocity. Despite much work, the physical processes governing energy dissipation during these natural granular flows remain uncertain. Field observations show that large landslides travel over unexpectedly long distances, suggesting low dissipatio...
We investigate our capabilities of detecting and characterising mass wasting (e.g., slope streaks) with the seismometer SEIS/InSight in Elysium Planitia.
The texture, composition, and morphology of dunes observed in the equatorial regions of Titan may reflect present and/or past climatic conditions. Determining the physio‐chemical properties and the morphodynamics of Titan's dunes is therefore essential to understanding of the climatic and geological history of the largest moon of Saturn. We quantit...
Mountainous landscape evolution under tropical and alpine environments is mainly dictated by climatic forcing which influences underlying mechanisms of geomorphic transport (e.g., soil formation, river dynamics, slope stability and mass wasting). The time scale over which this influence acts ranges from seasonal to decennial time span. On the seaso...
On the seasonal time scale, for accessible locations and when manpower is available, direct observations and field survey are the most useful and standard approaches. However very limited studies have been conducted on direct observation at the decennial to century time-scale due to observational constrains. Here, we present an open and reproducibl...
Since early 2019, the InSight mission has proven that Mars is seismically active, with more than 900 seismic events recorded. Among them, several events have characteristics close to terrestrial tectonic earthquakes. Most of these events are located on the major graben system of Cerberus Fossae and, a little further north, on the secondary system o...
Titan's rich and dense atmosphere, composed mainly of methane and nitrogen, maintains a methane cycle that shapes its surface, like the water cycle on Earth. Methane precipitations erodes Titan's surface and forms complex river networks observed at all latitudes by the Cassini-Huygens mission. However, precipitation rates are poorly constrained and...
The NASA InSight mission to Mars successfully landed on 26 November 2018 in Elysium Planitia. It aims to characterize the seismic activity and aid in the understanding of the internal structure of Mars. We focus on the Cerberus Fossae region, a giant fracture network ∼1,200 km long situated east of the InSight landing site where M ∼3 marsquakes wer...
In response to ESA’s “Voyage 2050” announcement of opportunity, we propose an ambitious L-class mission to explore one of the most exciting bodies in the Solar System, Saturn’s largest moon Titan. Titan, a “world with two oceans”, is an organic-rich body with interior-surface-atmosphere interactions that are comparable in complexity to the Earth. T...
The rate of occurrence of High Frequency (HF) marsquakes, as recorded by InSight at Homestead Hollow, Elysium Planitia, increased after about LS=33∘, and ceased almost completely by LS=187∘, following an apparently seasonal variation with a peak rate near aphelion. We define seismic rate models based on the declination of the Sun, annual solar tide...
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On the seasonal time scale, for accessible locations and when manpower is available, direct observations and field survey are the most useful and standard approaches. However very limited studies have been conducted on direct observation at the decennial to century time-scale due to observational constrains. Here, we present an open and repr...
In response to ESA Voyage 2050 announcement of opportunity, we propose an ambitious L-class mission to explore one of the most exciting bodies in the Solar System, Saturn largest moon Titan. Titan, a "world with two oceans", is an organic-rich body with interior-surface-atmosphere interactions that are comparable in complexity to the Earth. Titan i...
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On the seasonal time scale, for accessible locations and when manpower is available, direct observations and field survey are the most useful and standard approaches. However very limited studies have been conducted on direct observation at the decennial to century time-scale due to observational constrains. Here, we present an open and repr...
div>
On the seasonal time scale, for accessible locations and when manpower is available, direct observations and field survey are the most useful and standard approaches. However very limited studies have been conducted on direct observation at the decennial to century time-scale due to observational constrains. Here, we present an open and repr...
div>
On the seasonal time scale, for accessible locations and when manpower is available, direct observations and field survey are the most useful and standard approaches. However very limited studies have been conducted on direct observation at the decennial to century time-scale due to observational constrains. Here, we present an open and repr...
div>
On the seasonal time scale, for accessible locations and when manpower is available, direct observations and field survey are the most useful and standard approaches. However very limited studies have been conducted on direct observation at the decennial to century time-scale due to observational constrains. Here, we present an open and repr...
Context. The effects of space weathering and other alteration processes on the upper surface of Saturn’s icy moons are yet to be explored.
Aims. We present a thermophysical model parametrised by way of regolith properties such as porosity, grain size, and composition, as well as the local topography. The modelled surface temperature and apparent em...
Landslides are common features found on steep slopes on Mars and the role of water in their formation is an open question. Our study focuses on three young martian landslides whose mechanism of formation is unknown and knowing their formation mechanism could give us key information on recent martian climate and/or tectonics. They are less than 5 km...
For the 2007 International Forum on Landslide Disaster Management framework, our team performed several numerical simulations on both theoretical and natural cases of granular flows. The objective was to figure out the ability and the limits of our numerical model in terms of reproduction and prediction. Our benchmarking exercises show that for alm...
Aeolian activity, the movement of dust and sand by the wind, is common on Earth and has been observed on other planets, including Mars. A new Mars lander, InSight, has for the first time monitored aeolian changes by combining imaging with weather, seismic and magnetic field measurements. Sand grains are seen moving along the ground and dust is lift...
Depth-averaged thin-layer models are commonly used to model rapid gravity-driven flows such as debris flows or debris avalanches. However, the formal derivation of thin-layer equations for general topographies is not straightforward. The curvature of the topography results in a force that maintains the velocity tangent to the topography. Another cu...
Statistische Analyse der zeitlichen Verteilung von High Frequency Marsquakes, nachweis einer zeitlich variablen eventrate und quantitatives ranking möglicher physikalischer mechanismen.
EP023-08
The NASA InSight mission on Mars is a unique opportunity to study atmospheric processes both from orbit and in situ observations. We use post-landing high-resolution satellite images (HiRISE) to monitor dust devil activity during almost one martian year. We detected and mapped newly formed dust devil tracks and analyze their characteristic...
River valleys have been observed on Titan at all latitudes by the Cassini‐Huygens mission. Just like water on Earth, liquid methane carves into the substrate to form a complex network of rivers, particularly stunning in the images acquired near the equator by the Huygens probe. To better understand the processes at work that form these landscapes,...
A key point of landslide hazard assessment is the estimation of their runout. Empirical relations linking angle of reach to volume can be used relatively easily, but they are generally associated with large uncertainties as they do not consider the topographic specificity of a given study site. On the contrary, numerical simulations provide more de...
A new 1.5 m diameter impact crater was discovered on Mars only ~40 km from the InSight lander. Context camera images constrained its formation between 21 February and 6 April 2019; follow‐up High Resolution Imaging Science Experiment images resolved the crater. During this time period, three seismic events were identified in InSight data. We derive...
The NASA InSight mission on Mars is a unique opportunity to study atmospheric processes both from orbit and in situ observations. We use post-landing high-resolution satellite images to monitor dust devil activity during the first eight months of the mission. We perform mapping and semi-automatic detection of newly formed dust devil tracks and anal...
Mass wasting erodes hillslopes and supplies sediments to catchment rivers (Schuster & Highland, 2007). To assess sediment transports in drainage networks, it is crucial to (1) estimate the volume of sediment delivered to the drainage network, and (2) evaluate the time needed and processes involved in rivers to evacuate these sediments out of the wa...
The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in Elysium Planitia on Mars on 26 November 2018 and fully deployed its seismometer by the end of February 2019. The mission aims to detect, characterize and locate seismic activity on Mars, and to further constrain the internal structure, comp...
The atmosphere of Mars is thin, although rich in dust aerosols, and covers a dry surface. As such, Mars provides an opportunity to expand our knowledge of atmospheres beyond that attainable from the atmosphere of the Earth. The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) lander is measuring Mars’s atmosph...
The atmosphere of Mars is thin, although rich in dust aerosols, and covers a dry surface. As such, Mars provides an opportunity to expand our knowledge of atmospheres beyond that attainable from the atmosphere of the Earth. The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) lander is measuring Mars’s atmosph...
Die Aktivität der sog. High Frequency Marsbeben (Ereignisse mit einem Frequenzgehalt dominant oberhalb von 2.4 Hz) nahm von Mai bis August 2019 zunächst stark zu, hielt dann (während des Nord-Sommers) auf hohem Niveau an und klang im Frühjahr 2020 fast vollständig ab. Es ist vorgeschlagen worden (Manga et al., 2019, https://doi.org/10.1029/2019GL08...
The texture, composition, and morphology of dunes observed in the equatorial regions of Titan may reflect present and/or past climatic conditions. Determining the physio-chemical properties and the morphodynamics of Titan's dunes is therefore essential to understanding of the climatic and geological history of the largest moon of Saturn. We quantit...
InSight landed on Mars on November 26, 2018 in western Elysium Planitia. The Mars crust beneath the lander is subject to complex geologic history next to the great topographic and crustal dichotomy of Mars. Understanding this part of the Martian crust in the subsurface would aid future investigations of the internal structure of the planet based on...
Supplementary Information of manuscript Texture and composition of Titan's equatorial sand seas inferred from Cassini SAR data: Implications for aeolian transport and dune morphodynamics
A. Lucas, S. Rodriguez, F. Lemonnier*, A. Le Gall, S. MacKenzie, C. Ferrari, Ph. Paillou, C. Narteau
Accepted for JGR-E, 2019JE005965, pre-print is available on ar...
In this white paper, we present a cross-section of important scientific questions that remain partially or completely unanswered, ranging from Titan exosphere to the deep interior, and we detail which instrumentation and mission scenarios should be used to answer them. Our intention is to formulate the science goals for the next generation of plane...
Titan, Saturn’s largest moon, hosts lakes and seas of liquid hydrocarbons at its poles¹. General circulation models demonstrate that regional evaporation and precipitation rates of methane are likely to change with the seasons (Titan’s year is 29.5 Earth years) and evolve on a geological timescale (~10⁵ Earth years)2–4. Cassini observations suggest...
InSight carries a sophisticated Meteorological Station and has observed a dust storm, baroclinic waves, thermal tides, gravity waves, undular bores, convective vortices (with dust cleaning), infrasound, clouds and aeolian change. We report on these.
Titan was a mostly unknown world prior to the Cassini spacecraft’s arrival in July 2004. We review the major scientific advances made by Cassini’s Titan Radar Mapper (RADAR) during 13 years of Cassini’s exploration of Saturn and its moons. RADAR measurements revealed Titan’s surface geology, observed lakes and seas of mostly liquid methane in the p...
Some of the most spectacular instances of deep-seated gravitational slope deformation (DSGSD) are found on Mars in the Valles Marineris region. They provide an excellent opportunity to study DSGSD phenomenology using a scaling approach. The topography of selected DSGSD scarps in Valles Marineris and in the Tatra Mountains is investigated after thei...
Mars is dry today, but numerous precipitation-fed paleo-rivers are found across the planet's surface. These rivers' existence is a challenge to models of planetary climate evolution. We report results indicating that, for a given catchment area, rivers on Mars were wider than rivers on Earth today. We use the scale (width and wavelength) of Mars pa...
https://www.hou.usra.edu/meetings/lpsc2019/pdf/1825.pdf
https://www.hou.usra.edu/meetings/lpsc2019/pdf/2390.pdf
Understanding what controls the travelling distance of large landslides has been the topic of considerable debate. By combining observation and experimental data with depth-averaged continuum modelling of landslides and generated seismic waves, it was empirically observed that lower effective friction had to be taken into account in the models to r...
Introduction: Landscapes of Titan, the largest moon of Saturn, were observed during nearly 13 years in the frame of the Cassini-Huygens mission. The wide variety of morphologies observed (dunes, mountains, seas, lakes, rivers...) testifies to the geological richness that Titan shares with the Earth. In order to better understand the processes at wo...
During thirteen years (2004-2017), the Cassini-Huygens mission revealed that Titan is is a frozen version of Earth, where methane behaves as water, organic matter as sediment, and where water ice may be as hard as rock. Consequently, Titan experiences a large variety of surface processes that involve exchange between its surface and its atmosphere....
Impact investigations will be an important aspect of the InSight mission. One of the scientific goals of the mission is a measurement of the current impact rate at Mars. Impacts will additionally inform the major goal of investigating the interior structure of Mars.
In this paper, we review the current state of knowledge about seismic signals from...
The French critical zone initiative, called OZCAR (Observatoires de la Zone Critique–Application et Recherche or Critical Zone Observatories–Application and Research) is a National Research Infrastructure (RI). OZCAR-RI is a network of instrumented sites, bringing together 21 pre-existing research observatories monitoring different compartments of...
In November 2018, for the first time a dedicated geophysical station, the InSight lander, will be deployed on the surface of Mars. Along with the two main geophysical packages, the Seismic Experiment for Interior Structure (SEIS) and the Heat-Flow and Physical Properties Package (HP³), the InSight lander holds a highly sensitive pressure sensor (PS...
Saturn’s moon Titan has a dense nitrogen-rich atmosphere, with methane as its primary volatile. Titan’s atmosphere experiences an active chemistry that produces a haze of organic aerosols that settle to the surface and a dynamic climate in which hydrocarbons are cycled between clouds, rain and seas. Titan displays particularly energetic meteorology...