Tsunamis can produce catastrophic damage on vulnerable coastlines, essentially following major earthquakes, landslides or atmospheric disturbances. After the disastrous tsunamis in 2004 and 2011, tsunami science has grown significantly, opening new fields of research for various domains, and also in regions where the tsunami hazard was previously underestimated.
Numerical modeling, complemented with laboratory experiments, are essential to quantify the tsunami hazard. To this end, it is essential to rely on complete databases of past tsunami observations, including both historical events and results of paleotsunami investigations. Furthermore, a robust hazard analysis has to take into account uncertainties and probabilities with the more advanced approaches such as PTHA.
Because the vulnerability of populations, of infrastructures and of the built environment in coastal zones increases, integrated plans for tsunami risk prevention and mitigation should be encouraged in any exposed coastline, consistent with the procedures now in place in a growing number of Tsunami Warning System.

The tsunami session welcomes multidisciplinary contributions covering any of the aspects mentioned here, encompassing field data, regional hazard studies, observation databases, numerical modeling, risk studies, real time networks, operational tools and procedures towards a most efficient warning.

A focus on recent tsunami events all over the globe is encouraged, as well as on the achievements of recent research and operational projects.

The scope of this session includes different aspects of large-amplitude wave phenomena in the ocean such as freak or rogue waves, surface and internal waves, as well as waves trapped by currents and bathymetry. The session is focused on the understanding of the physical mechanisms which cause extreme events, and the derivation of appropriate mathematical models for their description and advanced methods for their analysis. An essential part of such studies is the validation of new models and techniques versus laboratory and in-situ data. Special attention is paid to the description of wave breaking processes, and the interaction of large-amplitude waves with coastal structures.

Tsunamis and storm surges pose significant hazards to coastal communities around the world. Geological investigations, including both field studies and modelling approaches, significantly enhance our understanding of these events. Past extreme wave events may be reconstructed based on sedimentary and geomorphological evidence from low and high energy environments, from low and high latitude regions and from coastal and offshore areas. The development of novel approaches to identifying, characterising and dating evidence for these events supplements a range of established methods. Nevertheless, the differentiation between evidence for tsunamis and storms still remains a significant question for the community. Numerical and experimental modelling studies complement and enhance field observations and are crucial to improving deterministic and probabilistic approaches to hazard assessment. This session welcomes contributions on all aspects of paleo-tsunami and paleo-storm surge research, including studies that use established methods or recent interdisciplinary advances to reconstruct records of past events, or forecast the probability of future events.

This session welcomes contributions presenting advances in, and approaches to, studying, modelling, monitoring, and forecasting of internal waves in stratified estuaries, lakes and the coastal oсean.

Internal solitary waves (ISWs) and large-amplitude internal soliton packets are a commonly observed event in oceans and lakes. In the oceans ISWs are mainly generated by the interaction of the barotropic tides with the bottom topography. Large amplitude solitary waves are energetic events that generate strong currents. They can also trap fluid with larvae and sediments in the cores of waves and transport it a considerable distance. ISWs can cause hazards to marine engineering and submarine navigation, and significantly impact on marine ecosystems and particle transport in the bottom layer of the ocean and stratified lakes. Contributions studying flows due to internal waves, their origin, propagation and influence on the surrounding environment are of great importance.
The scope of the session involves all aspects of ISWs generation, propagation, transformation and the interaction of internal waves with bottom topography and shelf zones, as well as an evaluation of the role of internal waves in sediment resuspension and transport. Breaking of internal-waves also drives turbulent mixing in the ocean interior that is important for climate ocean models. Discussion of parameterizations for internal-wave driven turbulent mixing in global ocean models is also invited.

Coastal areas are vulnerable to ocean, atmospheric and land-based hazards. This vulnerability is likely to be exacerbated in future with, for example, sea level rise, changing intensity of tropical cyclones, increased subsidence (e.g. from groundwater extraction, tectonics), and increasing socio-economic development coupled to coastal squeeze in, particularly, the urbanised low elevation coastal zone. This calls for a better understanding of the underlying physical processes and their interaction with the coast. Numerical models therefore play a crucial role in characterizing coastal hazards and assigning risks to them. Drawing firm conclusions about current and future changes in this environment is challenging because uncertainties are often large, such as coastal impacts of likely and unlikely (also called high-end) sea level changes for the 21st century. Furthermore, studies addressing coastal impacts beyond this century pose new questions regarding the timescale of impacts and adaptation activity. This session invites submissions focusing on assessments and case studies at global and regional scales of potential physical impacts of tsunamis, storm surge, sea level rise, waves, and currents on coasts. We also welcome submissions on near-shore ocean dynamics and also on the socio-economic impact of these hazards along the coast.

Subaqueous mass movements include landslides, debris flows and turbidity currents. Their far-reaching impacts threaten densely-populated coastal regions, global economies and the environment. They have the potential to generate devastating tsunamis, severely damage seafloor infrastructure and transport vast amounts of sediment and microplastics to the ocean floor. They also play an important role in the deep sea burial of organic carbon.

Although often compared to their subaerial counterparts, run-out distances of subaqueous mass movements may be substantially greater (hundreds of kilometres), and can occur at remarkably lower gradients (

The study of active tectonic structures in offshore areas has been hampered by the scarcity of direct observations and by the limited resolution of indirect data. Nevertheless, in the last years, the development of new geophysical instrumentation and the acquisition of high-resolution bathymetric and active and passive seismic data (i.e., chirp, parametric sounder, multichannel profiles or OBS information) has allowed making major advances in the study of active faults in offshore areas. These new data have become fundamental not only to identify and describe active tectonic structures but also to characterize their Quaternary activity and seismogenic potential. Together with these developments, our understanding of marine active tectonics and our knowledge about their associated hazards have also improved.
The aim of this session is to compile studies which focus on the use of geophysical data to identify and characterize offshore active structures (i.e., faults and folds), their seismogenic and tsunamigenic potential and possibly related features such as submarine landslides, and to estimate the related hazards. Studies can be focused at regional or local scale and the session includes but is not limited to, the following topics:
- Active faulting identification and description and/or 3D modeling.
- Contribution of seismicity analysis to the seismotectonic characterization of offshore areas.
- Seismogenic characterization of active structures and estimation of their tsunamigenic potential.
- Active tectonics processes related to landslides triggering.
- Contribution of marine active tectonic study to the hazard assessment.

Oceanographic monitoring and modeling are both widely used to study the pathways and fate of marine pollutants such as hydrocarbons, marine litter, POPs, HNS, radionuclides, etc. In this session, advanced sampling methods, models, operational applications and techniques related to tracing pollutants on local, regional and global scales, as well as the coupling with met-oceanographic transport fields from operational oceanography products such as Copernicus Marine Monitoring Environment Service will be discussed. State-of-the-art observational techniques and protocols, ensemble and multi-model methods, risk assessment algorithms and decision support systems are solicited topics. Integration of modelling and observing systems for both data assimilation and model validation are also very welcome.
Key questions of the session are identified as follows: Which factors affect the dispersion of the pollutants in the marine environment? What happens to the contaminants on the ocean’s surface, in the water column and sediments? How do marine pollutants interact with marine habitats? How do they influence marine and maritime resources? How should Integrated Coastal Zone Management (ICZM) protocols be optimized to minimize negative impact on the coastal zone?
Impacts of pollutants, including light and noise pollution, on the marine ecosystems and resilience to pollution events are also important subjects for discussion: What is the behavior of oil, marine litter, heavy metals, and other pollutants in the water column, on various beach sediments, rocks and seabed? e.g., what is the biodegradation rate of oil droplets in the water column and what are the controlling factors? What is the rate of fragmentation, biofouling, and sedimentation of plastics? What are the mechanisms of beaching, seabed deposition, and resuspension of marine pollutants and what are the ways of entering the marine food chains (including human consumption)? What is the impact of light and noise pollution on the marine environment and habitats?

This session is open to science on the tides of the ocean, atmosphere and solid earth; on spatial scales from global to coastal, estuarine and river; and on all timescales. Tides can cause flooding, particularly in combination with storm surge, and tidal currents and water levels can be both a help and a hindrance to shipping and energy generation. There is a critical role for tides in ocean mixing and the cryosphere, and accurate tide models are required for the processing of remote sensing and satellite geodesy data.
We welcome presentations on progress in modelling of past, present, and future tides, assessment of the accuracy of tide models, novel methods for tide predictions, advances in instrumentation and data processing, new findings from the analysis of historical tide gauge data, and understanding of secular changes in tides due to sea-level change and other environmental forcing factors. We also invite submissions on tides of lakes and of other planets.
Déborah Idier of BGRM, the French Geological Survey, will give the invited presentation for this session, on the mechanisms of changes to tides on the European Shelf under sea-level rise.

This session provides a platform for cross-disciplinary science that addresses the continuum of the river and its catchment to the coastal sea. We invite studies across geographical borders; from the source to the sea including groundwater, and across the freshwater-marine water transition. The session welcomes studies that link environmental and social science, address the impacts of climate change and extreme events, and of human activities on water and sediment quality and quantity, hydromorphology, biodiversity, ecosystem functioning and ecosystem services of River-Sea systems, and that provide solutions for sustainable management of the River-Sea social-ecological system.
We need to fully understand how River-Sea-Systems function. How are River-Sea-Systems changing due to human pressures? What is the impact of processes in the catchment on marine systems function, and vice versa? How can we discern between human-induced changes or those driven by natural processes from climate-induced variability and extreme events? What will the tipping points of socio-ecologic system states be and what will they look like? How can we better characterise river-sea systems from the latest generation Earth observation to citizen science based observatories. How can we predict short and long term changes in River-Sea-Systems to manage them sustainably? What is the limit to which it is possible to predict the natural and human-influenced evolution of River-Sea-Systems? The increasing demand to jointly enable intensive human use and environmental protection in river-sea systems requires holistic and integrative research approaches with the ultimate goal of enhanced system understanding.

Since 2004, there have been a number of large subduction earthquakes whose unexpected rupture features contributed to the generation of devastating tsunamis. The impact that these events have had on human society highlights the need to improve our knowledge of the key mechanisms behind their origin. Advances in these areas have led to progress in our understanding of the most important parameters affecting tsunamigenesis.

With increasing geophysical data, new descriptions of faulting and rupture complexity are being hypothesized (e.g., spatial and temporal seismic rupture heterogeneity, fault roughness, geometry and sediment type, interseismic coupling, etc.). Rock physicists have proposed new constitutive laws and parameters based on a new generation of laboratory experiments, which simulate close to natural seismic deformation conditions on natural fault samples. In addition, advances in numerical modelling now allow scientists to test how new geophysical observations, e.g. ocean drilling projects and laboratory analyses, influence subduction zone processes over a range of temporal and spatial scales (i.e., geodynamic, seismic cycling, earthquake rupture, wave propagation modelling).

In light of these advances, this session has a twofold mission: i) to integrate recent results from different fields to foster a comprehensive understanding of the key parameters controlling the physics of large subduction earthquakes over a range of spatial and temporal scales; ii) to identify how tsunami hazard analysis can benefit from using a multi-disciplinary approach.

We invite abstracts that enhance interdisciplinary collaboration and integrate observations, rock physics experiments, analog- and numerical modeling, and tsunami hazard.

Modelling the interaction of water waves with varying current is an important issue, especially in nearshore and coastal areas and for a variety of engineering applications.
These applications include wave structure interactions, with the problematics related to oil and naval industries, but also renewable energies.
The problematic is also important when considering coastal management, and harbour maintenance and exploitation.
Also, this interaction often leads to the formation of extreme wave events with detrimental effects.
Significant scientific effort was undertaken during the last fifty years to model linear, weakly or strongly nonlinear water waves with constant, or slowly varying currents.
When variations are stronger, the difficulty remains important.
In this session, contributions are invited relating experimental, numerical and theoretical works designed to improve the understanding of water waves and current interactions, including wave and current stability, wave dynamics, and energy propagation.
Contributions describing the specific problematics, from the point of the applications, are also deeply welcome.

Scientific drilling through the International Ocean Discovery Program (IODP) and the International Continental Scientific Drilling Program (ICDP) continues to provide unique opportunities to investigate the workings of the interior of our planet, Earth’s cycles, natural hazards and the distribution of subsurface microbial life. The past and current scientific drilling programs have brought major advances in many multidisciplinary fields of socio-economic relevance, such as climate and ecosystem evolution, palaeoceanography, the deep biosphere, deep crustal and tectonic processes, geodynamics and geohazards. This session invites contributions that present and/or review recent scientific results from deep Earth sampling and monitoring through ocean and continental drilling projects. Furthermore, we encourage contributions that outline perspectives and visions for future drilling projects, in particular projects using a multi-platform approach.

Public information:
Please find below messages to the international scientific drilling community from Gilbert Camoin (Director of the ECORD Managing Agency) and Marco Bohnhoff (ICDP Executive Director), at this most difficult time resulting from the COVID-19 crisis:

Message from ECORD/IODP, Director ECORD Management Agency:

Science knowledge over the last 50 years of ocean drilling has greatly enhanced our understanding of the Earth system. Since its creation in 2003, ECORD has played a leading role in the successive ocean drilling programmes. During 2019, the scientific ocean drilling community took a unique multi-decadal approach to formulating the future of this international program in the new 2050 Science Framework: Exploring Earth by Scientific Ocean Drilling. The unprecedented health crisis related to the COVID-19 disease outbreak is severely affecting the activities of our programme, but the scientific ocean drilling community remains mobilized for a brighter future. In these different times, I do hope that you and your loved ones will stay safe and healthy.

Message from the ICDP Executive Director Marco Bohnhoff:

COVID-19 is having a huge impact on society as a whole and the personal life of most of us has been turned upside down. However, ICDP is also active in times of COVID-19. A new ICDP Science Plan for the time after 2021 is currently being prepared and will be published in the second half of 2020. For those who submitted drilling or workshop proposals this year: the ICDP Panels will meet online between May 11-16 and decide about your proposals. Good news is also that the COSC-2 drilling is Sweden runs very successful, passing a depth of 500 m on April 30. Whether the ICDP training course can take place in October as planned is currently still open. Please check the ICDP website or our social media channels regularly for updates. I wish you a successful EGU session, stay healthy, and I look forward to seeing you again, hopefully soon.

The nature of science has changed: it has become more interconnected, collaborative, multidisciplinary, and data intensive. The main aim of this session, now in its third edition, is to create a common space for interdisciplinary scientific discussion where EGU-GA delegates involved in recent and ongoing COST (European Cooperation in Science and Technology)* Actions can share ideas and present the research activities carried out in their networks. The session represents an invaluable opportunity for different Actions and their members to identify possible synergies and establish new collaborations, find novel links between disciplines, and design innovative research approaches. So far, this session has hosted contributions stemming from 26 Actions, covering different areas of the geosciences (sky, earth and subsurface monitoring, terrestrial life and ecosystems, earth's changing climate and natural hazards, sustainable management of resources and urban development, environmental contaminants, and big data); we are looking forward to receiving new contributions this year.

Same as in past editions, part of this session will be dedicated to presenting and discussing activities carried out in further national and international scientific networks, associations, and collaborative projects.

Moreover, this session is of course open to everyone and abstracts authored by individual scientists or small research teams are most welcome, too. Actually, in 2018 and 2019 we received a very good number of such abstracts, submitted by researchers who wanted to disseminate the results of their studies in front of the multidisciplinary audience that characterizes this session, as an alternative to making a presentation in a thematic session. In fact, contributing to this session can be a productive way to broaden the perspective and find new partners for future interdisciplinary research ventures.

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* COST (www.cost.eu) is funded by the EU and enables researchers to set up their interdisciplinary and international scientific networks (the “Actions”). Academia, industry, public- and private-sector laboratories work together in the Actions, sharing knowledge, leveraging diversity, and pulling resources. Every Action has a main objective, defined goals and deliverables. This session is a follow-up initiative of COST Action TU1208 “Civil engineering applications of Ground Penetrating Radar” (www.gpradar.eu).