Landscapes Live is a weekly online seminar series freely accessible to the international scientific community interested in various aspects of geomorphology. Our talks take place on Zoom every Thursday, starting at 4pm time of Paris/Berlin/Amsterdam. Check your local time here.
Landscapes Live is affiliated to the Geomorphology (GM) division of EGU and contribute to develop its virtual activities. Indeed, EGU is pioneering a new CampFire concept to bring together the geoscience community in between General Assemblies. We hope that this will meet the needs of the current pandemic but also help us in our transition to a greener future and ensure that our community better serve the needs of all scientists regardless of international mobility.
Upcoming talks.....
Program (Fall 2024):
Thursday, 3 October 2024 at 16:00 CEST
Eric Barefoot (University of California Riverside, USA)
Zoom link: https://virginia.zoom.us/meeting/register/tJMrde-hpjgiH9dcxKrpnhjOwHJGJhqHB495
Title: Experimental Constraints on the Morphology of Canyons Formed by Crater Overtopping
Abstract: Crater rims on Mars and glacial moraines on Earth can both impound water to function as natural dams. When these dams fail, water overtopping the dam erodes the dam crest, increasing the aperture for flow and thus the discharge (a positive feedback). However, sediment eroded from the dam crest deposits downstream, lowering the topographic gradient. Additionally, as water drains from the lake, the water level will fall. Both of these effects decrease the discharge (negative feedbacks). Using a simplified 1D morphodynamic model and a set of flume experiments, we show that competition between these three feedback mechanisms determines which dams are vulnerable to catastrophic outburst floods. We find that the key controls are (1) the cross-sectional geometry of the initial dam and (2) the lake hypsometry. We compare these experimental and modeling results to the long profiles of canyons exiting known breached craters on Mars. Using this method, we tighten constraints on outburst-flood hydrographs and the water-mass balance of crater fill-and-spill events.
Thursday, 10 October 2024 at 16:00 CEST
Jérôme Lavé (CNRS, CRPG Nancy, France)
Zoom link: https://gfz-potsdam-de.zoom-x.de/meeting/register/u5EsduygrTsiGNzXVQYlpViz7B8SBhVRTDOq
Title Giant collapses of high Himalayan peaks and their implications on the Himalayan landscapes
Abstract: Although the topographic evolution and erosion dynamics of the Himalayan range have been extensively documented, it is not known how the very high Himalayan peaks erode. Some conceptual models assume that intense periglacial processes involve regressive erosion of high peak headwall at rates dictated by valley-floor downcutting of glaciers. However, recent data indicate that frost-cracking intensity decreases with elevation, suggesting instead that highest Himalayan peaks are free of erosion, raising the question of their long-term evolution. Here, we report geological evidence for two Holocene giant rockslides that occurred in the Annapurna Massif (central Nepal), involving total rock volume of ~23 and ~18 km3 respectively and that decapitated high paleosummits, culminating most probably above 8000 m altitude for the first one. Our data demonstrate that the main mode of high-altitude erosion could be catastrophic mega-rockslides, leading to the sudden reduction of the high peaks elevation by several hundred meters and ultimately preventing the high Himalayan peaks from growing indefinitely. This erosion mode, associated to steep slopes and high relief, arises from a higher mechanical strength of the high-peak substratum, probably due to the presence of permafrost at high altitude and the absence of bedrock weathering. In addition to their direct impact on the evolution of the High Himalayan landscape and ridgeline, giant rockfalls can also have major implications for the evolution of downstream rivers and natural hazards through massive sediment supply; but this effect mainly depends on the location of the rockfall within the range.
Thursday, 17 October 2024 at 16:00 CEST
Gareth Roberts (Imperial College London, UK)
Zoom link: https://gfz-potsdam-de.zoom-x.de/j/64493983170?pwd=3uwsIDjO4iKX2aHo3lSdeCa6VULk0J.1
Title: Embracing scale and erosional randomness to understand landscape evolution
Abstract: In this talk I will discuss work we have been doing to establish how landscapes evolve across scales of interest, e.g. less than a metre to thousands of kilometres, seconds to millions of years. I will briefly discuss observations and theory that suggest that the geomorphic consequences (e.g. shapes of longitudinal river profiles) of tectonic and diverse erosional process can be similar at large scales (>100 km, > 1 million years). I will also briefly discuss observations, and fundamental physics-based theory, which emphasise the importance of local conditions (e.g. orientation of joints and fractures, biota, hydrology) in generating fluvial geometries at small scales (e.g. less than a few kilometres and thousands of years). The bulk of the talk will focus on establishing how these scale-dependent insights can be reconciled. I will suggest stochastic theory, incorporating probability and randomness of erosion, as a means to generate a theory of fluvial erosion rooted in physics and self-consistent across scales. I will briefly introduce work we have been doing on this problem, making use of stochastic differential equations, developing analytical approaches that produce precise mathematical predictions of river profile shapes without recourse to numerical techniques, and how such a theory can be incorporated into linear programming (e.g. to predict river profile evolution across scales). I’ll talk about how the theory can be developed from first principles and used to understand the natural growth of erosional discontinuities (e.g. knickpoints), scale-dependent evolution, and local complexity existing within a framework of emergent simplicity. I’ll finish by discussing how stochastic theory gives means to bridge the considerable scale-gap between physics-based insights into fluvial erosion (e.g. from the lab, or field sites) and insights from phenomenological approaches (e.g. stream power models; inverse modelling for tectonic uplift histories at the scale of mantle convection).
Thursday, 24 October 2024 at 16:00 CEST
Aurélie Davranche (University of Helsinki, Finland; University of Angers, France)
Zoom link: https://videoconf-colibri.zoom.us/meeting/register/tJAqc-morzkoHNwpjPX4yGEShrlftQpc0cRL
Title: From field to space: multisource data to show how a nature based management can help to cope for sea level rise in the Mediterranean area
Abstract: In Camargue, a coastal wetland area on the border of the Mediterranean Sea, there is a strong dynamic of the coastline retreat with nearly 200 meters since the 1950s. While 2 solutions, a protective solution with dykes or a fallback solution, are being planned, a 3rd one is investigated in this study: a nature-based management. Since 2010, the Conservatoire du Littoral, a public organization that protects coastal areas in France, has progressively purchased 65 km2 of former saltworks. The site hosts large areas of lagoons, Mediterranean salt steppes, coastal dunes and wooded dunes. It was exploited for industrial salt production with major transformations between the 1950's and early 1970's. The restoration of natural flooding patterns integrated in this adaptive management plan has favoured the development the NATURA 2000 habitat called “Mediterranean and thermo-Atlantic halophilous scrubs (Sarcocornetea fruticosi)” that decreased with the development of the saltworks industry from 1856 and the agriculture. In this study we used multi-source data from an interdisciplinary protocol including measurement of sediment sizes, analyses of satellite images and LIDAR acquisitions, and vegetation inventory in the field. From this multi-scale data gathering, we highlight the sediment distribution and flooding periods at the development places of the scrub vegetation on the borders of dunes. This study shows how the interdisciplinarity can help to promote nature-based solutions to face climate change, and how it is important to consider wetland ecological functions in management actions.
Thursday, 31 October 2024 at 16:00 CEST
Tancrède Leger (University of Lausanne, Switzerland)
Zoom link: https://virginia.zoom.us/meeting/register/tJwscu6urTotG9z58u-TXAe_Ltta44ItYDfI
Title: A data-consistent model of the last glaciation in the Alps achieved with physics-driven AI
Abstract: 25 thousand years ago, the European Alps were covered by a kilometre-thick body of ice, commonly described as the Alpine Ice Field. Numerical modelling of this glaciation has been challenged by persistent model-data disagreements, including large overestimations of its former thickness. Here, we tackle this issue by applying the Instructed Glacier Model, a three-dimensional, high-order, and thermo-mechanically coupled model enhanced with physics-informed machine learning. This new approach allows us to produce an ensemble of 100, Alps-wide and 17 thousand-year-long (35-18 ka) simulations at 300 m spatial resolution. Unfeasible with traditional models due to computational costs, our experiment substantially increases model-data agreement in both ice extent and thickness. The model-data offset in ice thickness, for instance, is here reduced by between 200% and 450% relative to previous studies. The results yield implications for more accurately reconstructing former ice velocities, ice temperature, basal conditions, glacial erosion processes, glacial isostatic adjustment, and climate evolution in the Alps during the last glaciation. Furthermore, this study demonstrates that physics-informed AI-driven glacier evolution models can overcome the bottleneck of high-resolution continental-scale modelling required to accurately describe complex topographies and ice dynamics.
Thursday, 7 November 2024 at 16:00 CET
Victoria Milanez Fernandes (GFZ, Germany)
Title TBD
Thursday, 14 November 2024 at 16:00 CET
Kaja Fenn (University of Liverpool, UK)
Title TBD
Thursday, 21 November 2024 at 16:00 CEST
Sinelethu Hashibi (University of Cape Town, South Africa)
Title TBD
Thursday, 28 November 2024 at 16:00 CEST
Lindsay Schoenbohm (University of Toronto, Canada)
Title TBD
Thursday, 28 November 2024 at 16:00 CEST
Edward Rhodes (University of Sheffield, UK)
Title TBD
Past speakers.....
Thursday, 6 June 2024 at 16:00 CEST
Nakul Deshpande (NC State University, USA)
The Perpetual Fragility of Creeping Hillslopes
Talk is now on LL's YouTube channel: https://youtu.be/JuRl9coHMIo
Thursday, 28 March 2024 at 16:00 CET
Katy Burrows (ESA)
Resolving the impacts of earthquakes, storms, and prolonged rainfall on shallow landsliding
Talk is now on LL's YouTube channel: https://www.youtube.com/watch?v=72yxOMXzfNs
Thursday, 4 April 2024 at 16:00 CEST
Albert Cabré (GET, Geoscience Environment Toulouse, France)
Geomorphic work of recent episodic rainstorm events in arid landscapes: examples from the Atacama Desert
Talk is now on LL's YouTube channel: https://www.youtube.com/watch?v=uKF473Pv1No
Thursday, 11 April 2024 at 16:00 CEST
Scott Jess (Washington State University, USA)
The ups and downs of extensional tectonics
Talk is now on LL's YouTube channel: https://www.youtube.com/watch?v=SQQFXh5aYIw
Thursday, 2 May 2024 at 16:00 CEST
Danica Roth (Colorado School of Mines, USA)
Unveiling nonlocal landscape dynamics: exploring hillslope processes beyond the diffusive paradigm
Talk is now on LL's YouTube channel: https://youtu.be/VJcZBe6thqQ
Thursday, 9 May 2024 at 16:00 CEST
Sam Woor (University of British Columbia & University of the Fraser Valley, Canada)
Illuminating landscape responses to Quaternary climate change with luminescence
Talk is now on LL's YouTube channel: https://www.youtube.com/watch?v=pDmnPb-FiLA
Thursday, 16 May 2024 at 16:00 CEST
Virginia Ruiz-Villanueva (University of Lausanne & University of Bern, Switzerland)
Quantifying and monitoring instream large wood supply and transfer in rivers
Talk is now on LL's YouTube channel: https://www.youtube.com/watch?v=38oT5MwHgX4
Thursday, 23 May 2024 at 16:00 CEST
Claire Masteller (Washington University in St. Louis, USA)
Wiggles in width: Insights into alluvial channel dynamics from variability in high-resolution downstream hydraulic geometry
Talk is now on LL's YouTube channel: https://www.youtube.com/watch?v=BMizP1choAE