Physical erosion and chemical weathering dominate the evolution of surface and subterranean mountain landscapes over a wide range of temporal and spatial scales. Signals from processes such as glacial and periglacial erosion, chemical and mechanical weathering, rockfall, debris flow, and hillslope failure are preserved in downstream patterns of river and/or valley aggradation and incision as well as in the development of karst systems and their sediment deposits. These processes react to a wide spectrum of external and internal forcings (e.g. climatic variability, tectonic activity, spatial patterns of vegetation or sudden internal failure) often making it difficult to relate these records back to specific causal mechanisms.

Measuring the dynamical interplay of erosion, weathering and sedimentation as well as quantifying the rates and fluxes associated with the evolution of mountainous landscapes, is a crucial but challenging component of source-to-sink sediment research. Many of these processes also pose serious threats to the biosphere, mountain settlements and infrastructure. Understanding and quantifying these processes from both a societal and engineering point of view will lead to better preparation and responses to such threats.

We welcome contributions that (1) investigate the processes of production, mobilisation, transport, and deposition of sediment in mountain landscapes, (2) study the development of cave systems and their sedimentary archive in relation to external base-level conditions and internal dynamics (3) explore feedbacks between erosion and weathering due to natural and anthropogenic forcings, (4) address the role these processes play in the larger source-to-sink context, and (5) consider how these processes contribute to natural hazards specific to mountain landscapes. We invite presentations that employ observational, analytical or modelling approaches in mountain environments across a variety of temporal and spatial scales. We particularly encourage early career scientists to apply for this session.

Public information:
Block 1 schedule:

14:00-14:10: A bit of time to explore the displays.
14:10: Oliver Francis D1106 EGU2020-891 The fate of sediment after a large earthquake
14:20: Rachel Glade (solicited) D1107 EGU2020-12761 River canyon evolution governed by autogenic channel-hillslope feedbacks
14:35: Benjamin Campforts D1108 EGU2020-13064 To slide or not to slide: explicit integration of landslides and sediment dynamics in a landscape evolution model
14:45: Philippe Vernant D1109 EGU2020-9099 First quantitative evidences of ghost-rock karstification controlling regional karst geometry
14:55: Robert Hilton D1112 EGU2020-5624 A shifting view of erosion and the carbon cycle
15:05: Stephanie Olen D1114 EGU2020-5939 Synthetic aperture radar coherence as a proxy for geomorphic activity
15:15: Eric Deal D1115 EGU2020-5510 Analytical long-profile models of coupled glacier-fluvial systems
15:25: Anna Masseroli D1119 EGU2020-749 Differentiation among geomorphological processes in a mountain hydrographic basin by means of soils analyses
15:35: Alex Beer D1122 EGU2020-12980 Bedrock Topographic Evolution from Rockfall Erosion

Block 2 schedule:
16:20: Sharon Pittau D1123 EGU2020-10391 A multi-temporal inventory for constraining earthflow source-to-sink pathways in the Sillaro River basin, Northern Apennines
16:30: Emma Graf D1126 EGU2020-455 Where does all the gravel go? Tracking landslide sediment from the 2015 Gorkha earthquake along the Kosi River, Nepal
16:40: Paul Krenn D1127 EGU2020-13255 Analysing the impacts of extreme precipitation events on geomorphic systems in torrential catchments; a comparative study from Upper Styria, Austria
16:50: Benjamin Purinton D1129 EGU2020-3943 Multiband (X, C, L) radar amplitude analysis for a mixed sand- and gravel-bed river in the eastern central Andes
17:00: Jinyu Zhang D1131 EGU2020-12497 Reconstructing aggradation and incision of the Lancang River (Upper Mekong) at Yunlong reach, southeast Tibet
17:10: Frank Lehmkuhl D1132 EGU2020-3893 Quaternary paleoenvironmental change preserved in alluvial fans systems in semiarid to arid mountain areas: Examples from western Mongolia, western USA, and the Chilean Andes
17:20: Erica Erlanger D1134 EGU2020-12043 Partitioning the denudation flux between silicate and carbonate physical erosion and chemical weathering in the Northern Apennines
17:30: Tim Jesper Suhrhoff D1136 EGU2020-18195 Weathering signals in Lake Baikal and its tributaries
17:40: Maarten Lupker D1137 EGU2020-4480 Chemical weathering pathways in the central Himalaya – new constraints from DI14C and δ34S
17:50: Luca Pisani D1140 EGU2020-3935 Karst porosity development in layered and fractured carbonates: field evidences of structural control on sulfuric acid speleogenesis (Majella Massif, Italy)

Land cover plays a key role for geomorphic processes in steep-land environments. It exhibits both beneficial and adverse effects on hillslope denudation and substantially influences landscape evolution. Land cover information becomes of fundamental importance in many applications for assessing soil erosion loss and landslide activity at difference scales, from local to global analysis. Apparent land cover of a landscape affects the accuracy of most investigations that aim to detect, observe, analyse, model or predict geomorphic and landform-shaping processes. In contrast, denudational processes have a strong impact on both natural ecosystems and cultivated land, leading from increasing environmental diversity to economic damages.
This session is designed to cluster the most recent scientific researches on the analyses, modelling and prediction of soil erosion and landslide processes that are directly linked to land cover dynamics. Such variations can alter the soil properties as soil reinforcement and soil aggregation, and make the modelling and prediction of higher complexity.
Studies that pay heed on the impact of land cover changes on shallow or deep-seated and transient or long-term slope instabilities as well as surface water flow and related soil erosion processes are welcome. Research abstracts are invited to address:
1. observation and detection of different land cover types, land use changes and occurrences of erosion or landslides using a wide spectrum of technologies, from field measurements to remote sensing techniques;
2. analyses on the relationship between land cover and geomorphic processes from local to regional scale;
3. prediction of impacts on surface water flow, erosion and slope stability due to land cover changes;
4. innovative modelling approaches for assessing soil instabilities (statistical, physically-based, numerical) that focus on model implementation, parameterisation, uncertainties and simulation of land cover evolution;
5. development of guidelines and regulations for practitioners, technicians, policy and decision makers.
We highly welcome pioneering research from all fields, especially from geomorphology, agricultural science, soil science, geotechnics and environmental engineering. In particular, young career scientists are encouraged to contribute to the session with original and advanced studies.

A key goal within geomorphic research is understanding the processes linking topographic form, erosion rates, and sediment production, transport and deposition. Numerical modelling, by allowing the creation of controlled analogues of natural systems, provides exciting opportunities to explore landscape evolution and generate testable predictions.

In this session, we invite contributions that use numerical modelling to investigate landscape evolution in a broad sense, and over a range of spatial and temporal scales. We welcome studies using models to constrain one or more of: erosion rates and processes, sediment production, transport and deposition, and sediment residence times. We also particularly wish to highlight studies that combine numerical modelling with direct Earth surface process monitoring techniques, such as topographic, field, stratigraphic, or geochronological data. Contributions using numerical models to unravel the interaction between environmental variables such as precipitation and lithology are further encouraged. There is no geographical restriction: studies may be focused on mountain environments or sedimentary basins, or they may establish links between the two. Studies beyond planet Earth are welcome too.

Denudation, including both chemical and mechanical processes, is of high relevance for Earth surface and landscape development and the transfer of solutes and sediments from headwater systems through main stem of drainage basin systems to the world oceans. Denudational hillslope and fluvial processes and associated source-to-sink fluxes and sedimentary budgets are controlled by a range of environmental drivers and can be significantly affected by climate change and anthropogenic activities.
The better understanding of possible effects of ongoing and accelerated environmental changes (including large-scale damming, hydrological change, and sediment mining) on present-day denudation requires systematic and quantitative studies on the actual drivers of denudational processes. Only if we have an improved quantitative knowledge of the drivers and rates of contemporary denudational hillslope and fluvial processes, as well as of the connectivity in landscapes and between hillslope and fluvial systems across a range of different spatio-temporal scales and selected climatic zones, can the possible effects of climatic changes and anthropogenic impacts and other disturbances be better assessed.
This session includes scientific contributions on denudational hillslope and fluvial processes, mass transfers, sedimentary budgets and landscape responses to ongoing and accelerated environmental changes in different climatic zones. Oral and poster contributions cover a wide range of different spatial scales, from hillslope and small headwater systems to large drainage basin systems. The session brings together and discusses a wide range of advanced techniques and methods of data collection and generation, including field-based, laboratory-based, remotely-sensed and dating techniques together with various approaches and methods of data analysis and geomorphologic modelling. The session seeks not only to identify the causes and drivers of changes in water, sediment and solute fluxes from "source-to-sink", but to also includes studies that present options for future sustainable management that recognise the particular characteristics and challenges of these complex systems.

The session is co-organized by the IAG Working Group on Denudation and Environmental Changes in Different Morphoclimatic Zones (DENUCHANGE).
Solicited speaker: Edgardo M. Latrubesse (Singapore)

In many parts of the world, landslide phenomena are a direct response to rapid environmental changes caused by global warming, human influences or other natural or technological hazards. The development of methods and strategies to evaluate hazard and risk posed by different types of landslides with different magnitudes in different environments has significantly progressed in the last decades due to rapid advance of computational and monitoring technologies. However, prognostic hazard and risk evaluations are highly challenged by the fact that local and regional environmental and meteorological conditions are subjected to rapid changes due to global warming and its consequences, modifying the local terrain susceptibility to landslides. Additionally, global change leads to significant changes in patterns of objects-at-risk due to population changes and concurring infrastructural developments.
This session aims to collect papers dealing with the advancement of methods and strategies for the prognostic spatio-temporal development of landslide hazard and risk scenarios and potentials in times of rapid global environmental change. Contributions dealing with the preparation and use of event-based landslide inventories for landslide hazard scenario assessments are welcomed as well as papers describing new advancements in process-oriented techniques for landslide hazard modelling at different spatial scales. Of particular interest are contributions concerned with the assessment of changing patterns of landslide-related risk posed to developing population and infrastructure in times of rapid environmental change.

Rockfalls, rockslides and rock avalanches are fundamental modes of erosion on steep hillslopes, and among the primary hazards in steep alpine terrain. To better understand the processes driving rock slope degradation, mechanisms contributing to the triggering, transport, and deposition of resulting rock slope instabilities, and mitigation measures for associated hazards, we must develop insight into both the physics of intact and rock mass failure and the dynamics of transport processes. This session aims to bring together state-of-the-art methods for predicting, assessing, quantifying, and protecting against rock slope hazards. We seek innovative contributions from investigators dealing with all stages of rock slope hazards, from weathering and/or damage accumulation, through detachment, transport and deposition, and finally to the development of protection and mitigation measures. In particular, we seek studies presenting new theoretical, numerical or probabilistic modelling approaches, novel data sets derived from laboratory, in situ, or remote sensing applications, and state-of-the-art approaches to social, structural, or natural protection measures.

This session covers an overview of the progress and new scientific approaches for investigating landslides using state-of-the-art techniques such as: Earth Observation (EO), close-range Remote Sensing techniques (RS) and Geophysical Surveying (GS).

A series of remarkable technological progresses are driven new scientific opportunities to better understand landslide dynamics worldwide, including integrated information about rheological properties, water content, rate of deformation and time-varying changes of these parameters through seasonal changes and/or progressive slope damage.

This session welcomes innovative contributions and lessons learned from significant case studies and/or original methods aiming to increase our capability to detect, model and predict landslide processes at different scales, from site specific to regional studies, and over multiple dimensions (e.g. 2D, 3D and 4D).

A special emphasis is expected not only on the particularities of data collection from different platforms (e.g. satellite, aerial, UAV, Ground Based...) and locations (e.g. surface- and borehole-based geophysics) but also on new solutions for digesting and interpreting datasets of high spatiotemporal resolution, landslide characterization, monitoring, modelling, as well as their integration on real-time EWS, rapid mapping and other prevention and protection initiatives. Examples of previous submissions include using one or more of the following techniques: optical and radar sensors, new satellite constellations (including the emergence of the Sentinel-1A and 1B), Remotely Piloted Aircraft Systems (RPAS) / Unmanned Aerial Vehicles (UAVs) / drones, high spatial resolution airborne LiDAR missions, terrestrial LIDAR, Structure-from-Motion (SfM) photogrammetry, time-lapse cameras, multi-temporal DInSAR, GPS surveying, Seismic Reflection, Surface Waves Analysis, Geophysical Tomography (seismic and electrical), Seismic Ambient Vibrations, Acoustic Emissions, Electro-Magnetic surveys, low-cost sensors, commercial use of small satellites, Multi-Spectral images, etc. Other pioneering applications using big data treatment techniques, data-driven approaches and/or open code initiatives for investigating mass movements using the above-described techniques will also be very welcomed.

GUEST SPEAKER: this year, we invited professor Jonathan Chambers, team leader of the geophysical tomography cluster at the British Geological Survey (BGS).

According to the Global Wildfire Information System, every year approximately 350 million hectares of land are affected by wildfires. This global phenomenon is responsible for substantial environmental, social and economic losses, which together with land abandonment, droughts, absence of appropriate land management and urban development planning, are expected to aggravate land degradation. In addition, wildfires are becoming a persistent threat, since the fire risk is expected to increase in a context of a warmer and drier climate.
This increased land degradation as a consequence of wildfires has also been highlighted in the latest Climate Change and Land, IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems. The impacts of wildfires on soils and ecosystems severely affect ecosystem services supply such as raw material and water provisioning, carbon storage, erosion and flood control, and habitat support, which are essential for human life. Therefore, attention of researchers, stakeholders and decision makers worldwide is urgently needed.
The aim of this session is to join researchers that study the effects of wildfires on ecosystems from wildfire prevention to post-fire mitigation. We warmly invite studies that approach:
i. prescribed and/or experimental fires;
ii. fire severity and burn severity;
iii. fire effects on vegetation, soils and water;
iv. post-fire hydrological and erosive response;
v. post-fire management and mitigation;
either by means of laboratory, field experiments, and/or numerical modelling.

Public information:
Short summary and feedback of the session
Our session aimed at bringing together researchers who study the effects of wildfires on ecosystems from wildfire prevention to post-fire mitigation. Overall, all the objectives of the session were addressed, and the main outcomes from this session agree in the need for a multidisciplinary approach to implement adequate pre-and post-fire management. It should be highlighted that many advances are being made:
• at the level of using remote-sense technologies to address wildfire risk and fuel connectivity within rural-urban interfaces;
• in the development of direct and indirect techniques to determine/estimate impacts of fires in soil properties;
• more than in the past, we can now observe more studies addressing post-fire mitigation treatments;
• the same way, several advances were made in modeling post-fire hydrological response and soil erosion processes.

Landslides are ubiquitous geomorphological phenomena with potentially catastrophic consequences. In several countries, landslide mortality can be higher than that of any other natural hazard. Predicting landslides is a difficult task that is of both scientific interest and societal relevance that may help save lives and protect individual properties and collective resources. The session focuses on innovative methods and techniques to predict landslide occurrence, including the location, time, size, destructiveness of individual and multiple slope failures. All landslide types are considered, from fast rockfalls to rapid debris flows, from slow slides to very rapid rock avalanches. All geographical scales are considered, from the local to the global scale. Of interest are contributions investigating theoretical aspects of natural hazard prediction, with emphasis on landslide forecasting, including conceptual, mathematical, physical, statistical, numerical and computational problems, and applied contributions demonstrating, with examples, the possibility or the lack of a possibility to predict individual or multiple landslides, or specific landslide characteristics. Of particular interest are contributions aimed at: the evaluation of the quality of landslide forecasts; the comparison of the performance of different forecasting models; the use of landslide forecasts in operational systems; and investigations of the potential for the exploitation of new or emerging technologies e.g., monitoring, computational, Earth observation technologies, in order to improve our ability to predict landslides. We anticipate that the most relevant contributions will be collected in the special issue of an international journal.

Public information:
EGU Session NH3.7

Welcome to the Session NH3.7 on Space and Time Forecast of Landslides

The chat session will proceed by maintaining the original order provided by the session program. However, only the presentations with actually uploaded material will be listed in the session chat list.

Authors will be introduced In groups of 3 and will have 1-2 minutes each, in sequence, to briefly introduce their work by copy-pasting some brief sentences that summarise the research

Afterwards, there will be 5-6 minutes devoted to questions by the audience to the 3 authors. Since Q&A will concern 3 different presentations at the same time, we ask both presenters and questioners to always state who is the recipient of each question and each answer, to avoid confusion.
For example, a correct question style could be: “@MarkSmith: could you please say something more on the landslide database?”

Conveners, acting as session chairs and moderators, will signal when question time is over. They will also collect and resubmit possible questions that have gone unanswered during the chat, if possible.

After each round of 3 author presentations and Q&A, the conveners will introduce the next three speakers.

At the end of the list, if additional time remains, the conveners will open a final discussion on the general topics of the session and on integrated questions transversal to 2 or more presentations.

We remember that participants are encouraged to keep discussing mutual interests on research topics also after the Session, by emailing each other.
Please note that in the Session Displays page, each abstract has a link icon where it is possible to directly email the abstract main author.

Best
FC, XF, FG, BT

Restoring degraded landscape, managing soil and water resources are important for human well-being. Hillslope management and bioengineering, reforestation, and torrent control work using transverse structures, such as check dams and more recently open check dams, are becoming more common to mitigate soil erosion and torrential hazards. Such techniques are particularly important as they control the flux of water, sediments, nutrients, and other solutes from headwaters to downstream in any watershed management. The design and criteria of the check dams are also facing challenges due to complex hydrological, geological, and biological processes that affect water and sediment transport over a wide range of spatial and temporal scales. However, there are still lack of long term monitoring and sufficient understanding on the effects of soil and water conservation techniques on soil erosion processes, vegetation restoration, and torrential hazards control. Integrated watershed management also becomes increasingly crucial to mitigate the unprecedented impacts of environmental changes (e.g. climate, land-use changes). In this fourth consecutive year of organizing the session during EGU, we welcome studies that focus on soil conservation techniques from hillslopes to watershed scale. Any contributions to the understanding of soil erosion control and sediment transport management based on detailed field monitoring, high-quality laboratory works, mathematic models and effectiveness assessment methods are welcomed. In particular, we propose an approach to join and share scientific and technical studies from all around the world related to the legacy effects of check-dams and the potential of open check dams, highlighting the role of complex interactions between ecological elements, geomorphic processes and engineering activities.

Public information:
Online Chat Schedule

08:30 (14:30 Beijing Time)
WELCOME to SSS2.9 online chat by convener team

08:32 (14:32) (Chairperson: Yang Yu)
D2135 | EGU2020-1236
Influence of Check Dams on Flood and Erosion Dynamic Processes of a Small Watershed in the Loss Plateau
Shuilong Yuan, Guoce Xu, Peng Shi, and Kexin Lu

08:40 (14:40) (Chairperson: Yang Yu and Peng Li)
D2136 | EGU2020-1361
Understorey vegetation drives surface runoff and soil loss in teak plantation-based system of Northern Laos
Layheang Song, Laurie Boithias, Oloth Sengtaheuanghoung, Chantha Oeurng, Christian Valentin, Phabvilay Sounyafong, Anneke de Rouw, Bounsamai Soulileuth, Norbert Silvera, Alain Pierret, and Olivier Ribolzi

08:48 (14:48) (Chairperson: Manuel Esteban Lucas Borja and Peng Li)
D2137 | EGU2020-1690
The Topography Meter: a measurement system applicable for gravity-erosion experiments using a novel 3D surface measuring technique
Xiangzhou Xu, Feilong Xu Xu, Wenzhao Guo, and Chao Zhao

08:56 (14:56) (Chairperson: Manuel Esteban Lucas Borja)
D2138 | EGU2020-2066
Distribution of soil organic carbon impacted by land-use change and check dam on the Loess Plateau of China
Peng Shi, Yan Zhang, Kexin Lu, Zhaohong Feng, and Yang Yu

09:04 (15:04) (Chairperson: Guillaume Piton)
D2140 | EGU2020-4738
Alternative approach for works controlling stony debris flows
Carlo Gregoretti, Matteo Barbini, Martino Bernard, and Mauro Boreggio

09:12 (15:12) (Chairperson: Manuel Esteban Lucas Borja and Peng Li)
D2143 | EGU2020-7441
Soil water flow behavior of abandoned farmland restored with different vegetation communities in the Loess Plateau of China
Rui Wang, Zhengchao Zhou, Ning Wang, Zhijing Xue, and Liguo Cao

09:20 (15:20) (Chairperson: Manuel Esteban Lucas Borja)
D2144 | EGU2020-1388
Plant root exerted a stronger positive effect on aggregate stability than soil during plant secondary succession on the Loess Plateau, China
Lie Xiao and Peng Li

09:28 (15:28) (Chairperson: Demetrio Antonio Zema)
D2145 | EGU2020-737
The magnitude of soil erosion of small catchments with different land use patterns under an extreme rainstorm on the Northern Loess Plateau, China
Nan Wang and Juying Jiao

09:36 (15:36) (Chairperson: Demetrio Antonio Zema)
D2146 | EGU2020-1232
Quantitative assessment of check dam system impacts on catchment hydrological response - a case in the Loess Plateau, China
Tian Wang, Zhanbin Li, Jingming Hou, Shengdong Cheng, Lie Xiao, and Kexin Lu

09:44 (15:44) (Chairperson: Demetrio Antonio Zema)
D2147 | EGU2020-1234
Effects of ecological construction on the transformation of different water types on Loess Plateau, China
Binhua Zhao and Zhanbin Li

09:52 (15:52) (Chairperson: Guillaume Piton and Peng Li)
D2150 | EGU2020-4779
Adaptation of the MMF (Morgan-Morgan-Finney) model to Mediterranean forests subject to wildfire and post-fire rehabilitation measures
Demetrio Antonio Zema, Joao Pedro Nunes, and Manuel Esteban Lucas-Borja

10:00 (16:00) (Chairperson: Guillaume Piton)
D2162 | EGU2020-9921
Check dams effects on plant and soil interface immediately after wildfire
Bruno Timóteo Rodrigues, Manuel Esteban Lucas-Borja, Demetrio Antonio Zema, and Yang Yu

10:08 (16:08) (Chairperson: Guillaume Piton)
D2164 | EGU2020-10009
Are site characteristics and channel hydro-morphology related with check dam functioning? A case study in México
Manuel Esteban Lucas-Borja, Bruno Gianmarco Carrà, Demetrio Antonio Zema, and Yang Yu

10:20 (16:20) A brief conclusion and closing SSS2.9 online chat by conveners
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The chat SSS2.9 will be available on 05 May, 08:30–10:15 (14:30-16:15, Beijing Time)

The consideration of entire “Source to Sink" systems is one of the most recent and challenging advance in earth surface dynamics and sedimentary geology. To understand S2S systems it is necessary to promote and enhance sharing of knowledge and concepts between previously separated disciplines that are involved in the analysis of S2S systems. In particular, studying S2S systems implies knowledge and skills from (1) geomorphology, which focuses on the understanding of erosion processes driving landform evolution and sediment fluxes, (2) stratigraphy/sedimentology, which focuses on the nature of sedimentary deposits and their distribution in time and space, and (3) tectonics and structural geology, which set the dimensions, geometry and dynamics of source/transfer areas and sedimentary basins (the sink). Understanding S2S systems also involves other Geosciences disciplines such as paleoclimatology and geochemistry, because they allow quantifying the factors controlling S2S systems dynamics (climatic controls on erosion, solid vs solute fluxes, etc.). The sedimentary record captures Earth’s environmental evolution through interactions with humans. Developing innovative strategies for shaping a sustainable future and responsible growth requires a holistic understanding of Earth’s resources and our impact on the environment that can be informed by the sedimentary archives.
The aim of this general session is to invite contributions from all S2S-related research fields in order to foster connections around a central theme and kickstart the emergence of a European S2S research community. In addition, we propose to use this session to initiate discussion on developing a strategy for S2S training of early-stage researchers to enable them to address the sedimentary system from source to sink and inform them of potential career opportunities in both the academic and non-academic sectors. We welcome all S2S-related and environmental signal propagation contributions, and in particular those addressing 1) perennial S2S dynamics in response to long-term tectonic and climatic signals in deep time, 2) transient S2S dynamics in response to short-term signals and extreme events, 3) generic S2S models inspired by nature, 4) relationships and feedbacks between human and S2S systems, 5) global to regional scale source-to-sink systems and the economic benefits of thinking in this mindset, and 6) innovative S2S training in academia and industry.

The dynamics of the solid Earth and its surface are strongly affected by their interplays as well as biota and climate. These constant feedback systems operate at a variety of spatial and temporal scales that are regulated in a complex system of interactions. For instance, in the critical zone -the terrestrial surface environment ranging from the lower atmosphere to the solid parent material- interplays not only regulate manifold ecosystems and bio-geochemical cycles, but also shape the Earth’s surface at the interface between atmosphere and lithosphere, where soils develop. At much larger scales, plate tectonics and global geodynamics control the physiography, climate and hydrosphere, which in turn strongly affect the surface feedback processes via tectonic, biological, geochemical and hydrological processes. Ultimately, climate and tectonics are prominent macro-ecological drivers of landscape development. But even though the underlying geology and tectonic processes have long been recognized as driving parameters, this is much less so for biological processes. The driving force of microorganisms, plants and animals on the shape of land surfaces is still poorly understood.
Understanding the links between the solid Earth and the external spheres of the Earth has experienced a recent upswing due to advanced analytical techniques, but also thanks to fostered interactions between researchers from different disciplines. This session aims to bring together geoscientists, soil scientists, climatologists and biologists working at different spatial and temporal scales on the feedback interactions between geology, topography, soils, climate and biosphere at the surface of the Earth. The session covers a multitude of topics from the microbial to the geodynamics time and space scales.

Solicited speakers are:
Carina Hoorn, University of Amsterdam, The Netherlands
Alexia Stokes, French National Institute for Agricultural Research – INRA, France
Veerle Vanacker, University of Louvain, Belgium

Large slope instabilities have been recognised in mountainous areas in different lithological and geological domains, and on other planets. Slow to extremely fast moving, complex mass movements have been recognized and sometimes described as strongly interrelated. Many types of slope instabilities can be grouped within this broad class, each presenting different types of hazard and risk. Some major aspects of these slope instabilities are still debated:
- regional distribution and relevance;
- presence, distribution and significance of phenomena on other planets;
- triggering and controlling factors;
- dating of initial movements and reactivation episodes;
- style and state of past and present activity;
- passive and/or active control by structural-tectonic elements;
- hydrological boundary conditions;
- possible evolution and modelling;
- assessment of related hazard;
- influence of anthropogenic factors and effects on structures;
- role on the erosional and sediment yield regime in drainage catchments and mountain belts;
- technologies for monitoring and warning systems, and the interpretation of monitoring data.
Study of these instabilities involves geology, geomorphology, geomechanics, hydro-geochemistry, and geophysics. For landslides on other planets a few of these approaches can be adopted making more difficult the interpretation of the phenomena, the identification of triggerings and controlling factors.
Trenching and drilling can be used for material characterization, recognition of activity episodes, which can be combined with monitoring data for establishing of warning thresholds and systems.
Geophysical survey methods can describe both the geometrical and geomechanical characteristics of the unstable mass. Dating techniques can be applied to determine the age of movements. Modelling can be applied to evaluate instability and failure, triggering (rainfall, seismicity, volcanic eruption, deglaciation), failure propagation, collapse (rock avalanches, debris avalanches and flows), and secondary failures (rockfall, debris flows).
Different hydraulic and hydrologic boundary conditions and hydrochemistry are involved, both at failure and during reactivations. The impacts of such instabilities on structures and human activities can be substantial and of a variety of forms. Furthermore, the local and regional sediment yield could be influenced by the landsliding activity and different landslides (e.g. type, size) can play different roles.

Rock deformation at different stress levels in the brittle regime and across the brittle-ductile transition is controlled by damage processes occurring on different spatial scales, from grain scale to fractured rock masse. These lead to a progressive increase of micro- and meso-crack intensity in the rock matrix and to the growth of inherited macro-fractures at rock mass scale. Coalescence of these fractures forms large-scale structures such as brittle fault zones and deep-seated rock slide shear zones. Diffuse or localized rock damage have a primary influence on rock properties (strength, elastic moduli, hydraulic and electric properties) and their evolution across multiple temporal scales spanning from geological times to highly dynamic phenomena as earthquakes, volcanic eruptions and landslides. In subcritical stress conditions, damage accumulation results in brittle creep processes key to the long-term evolution of geophysical, geomorphological and geo-engineering systems.

Damage and progressive failure processes must be considered to understand the time-dependent hydro-mechanical behaviour of faults (e.g. stick-slip vs asesismic creep), volcanic systems and slopes (e.g. slow rock slope deformation vs catastrophic rock slides), as well as the response of rock masses to stress perturbations induced by artificial excavations (tunnels, mines) and static or dynamic loadings. At the same time, damage processes control the brittle behaviour of the upper crust and are strongly influenced by intrinsic rock properties (strength, fabric, porosity, anisotropy), geological structures and their inherited damage, as well as by the evolving pressure-temperature with increasing depth and by fluid pressure, transport properties and chemistry. However, many complex relationships between these factors and rock damage are yet to be understood.

In this session we will bring together researchers from different communities interested in a better understanding of rock damage processes and consequence. We welcome innovative contributions on experimental studies (both in the laboratory and in situ), continuum / micromechanical analytical and numerical modelling, and applications to fault zones, reservoirs, slope instability and landscape evolution, and engineering applications. Studies adopting novel approaches and combined methodologies are particularly welcome.

Invited speakers:
- Brian Collins  (U.S. Geological Survey)
-  Jérôme Aubry  (Ecole Normale Supérieure de Paris)