Emma Hadré

Offshore freshened groundwater (OFG) is a significant yet underexplored component of the global water cycle, and its spatial distribution, particularly its links to past glacial processes, remains poorly constrained. The southeastern North Sea, characterized by extensive tunnel valley networks, provides an ideal setting to test how Pleistocene meltwater shaped offshore groundwater systems. Using newly acquired time-domain controlled-source electromagnetic data integrated with high-resolution seismic reflection surveys, we present a resistivity-based mapping of OFG in this region. The models reveal a laterally continuous OFG body with resistivities of 8–14 Ω·m, extending across multiple stratigraphic units and well beyond individual subglacial landforms. This configuration is best explained by subglacial meltwater flushing of sediment porewaters during Pleistocene glaciations. Subsequent preservation was aided by density contrasts that limit vertical mixing and by fine-grained glaciomarine deposits sealing the system from above. The connection between resistivity anomalies and mapped subglacial landforms shows that the latter can serve as predictive proxies for OFG occurrence. These findings shift the perspective from OFG as isolated anomalies to regionally extensive systems linked to glacial processes, establishing subglacial landforms as a testable screening proxy for locating OFG in formerly glaciated margins worldwide.

Gravitational volcanic flank collapses are recurrent processes producing large-scale landslides, commonly associated with secondary instabilities and destructive tsunamis. Ocean island volcanoes are particularly prone to such failures, yet the dynamics, emplacement mechanisms, and tsunamigenic potential of gravitational collapses remain poorly constrained due to the scarcity of direct observations. The ~ 68 ka Monte Amarelo flank collapse at Fogo, Cabo Verde, is one of the prominent examples of tsunamigenic gravitational collapses globally. But key parameters, including the collapse volume and the number of collapse stages, remain debated. We identify an extensive (914 km ² ) debris avalanche deposit associated with the Monte Amarelo volcanic flank collapse using high-resolution multibeam bathymetry and multichannel seismic reflection data. In addition, we find a smaller, previously unknown debris avalanche deposit superimposed on the northern half of the main deposit. Our results indicate that the Monte Amarelo collapse involved up to ~ 98 km ³ of material—the first volume estimate constrained by direct imaging of the submarine debris avalanche deposit through seismic data. The local morphology and internal structure of the main deposit suggest rapid emplacement and high tsunamigenic potential. The presence of a second deposit indicates multiple stages of collapse. Our results provide new constraints on the dynamics, volume, and sequence of events of one of the most recent gravitational collapses of a volcanic island in the Atlantic. These findings have important implications for tsunami generation and modelling and contribute to an improved understanding of hazards associated with gravitational collapses of volcanic islands.

Situated in the Cabo Verde Archipelago, Fogo is among the most active oceanic volcanoes in the Atlantic, hosting frequent eruptions some of which were highly explosive and at least one gravitational flank collapse in the last 100 kyr. This study presents new volcanic glass shard geochemical data with high spatial distribution from 54 sites comprising samples from both pre- and post-collapse times. The analyzed glasses comprise basanites, tephrites, and foidites with a subset extending into the phonolite field. The glass compositions complement bulk rock data particularly in the range between 6 and 1 wt.% MgO, thus enabling more detailed inter-dataset comparison. Major and trace element data reveal five geochemical Groups characterized by incompatible element contents partly delineating rock series. Compositional diversity is primarily controlled by fractional crystallization, and to lesser extents by mantle-source heterogeneity and degrees of partial melting. A geochemical framework is established for investigating provenance of ash and volcaniclastics in the Cabo Verde region and beyond by integrating new glass data with published bulk rock and tephra records. We validate the classification scheme through comparison with primary marine tephra deposits, demonstrating robust sample assignment to the observed compositional Groups. The new provenance data go beyond simple attribution to Fogo by resolving distinct compositional Groups, enabling improved discrimination within Fogo-derived material. Group assignment and characterization of differentiation trends provide a useful first-order indication of pre- versus post-collapse affinity. The glass dataset serves as a reference for future provenance and source correlation studies across the Cabo Verde Archipelago.

Submarine volcanic eruptions are among the least visible, yet very frequently occurring natural hazards, which makes them particularly challenging to address in school. With the WAVES project, we have developed an interactive outreach tool that combines a physical 3D model with a digital story map to support teaching about underwater volcanism, natural hazards, and Earth system processes.The tool is based on Kolumbo volcano in the Aegean Sea, which is one of the most active submarine volcanoes in Europe. This Aegean Sea region has experienced more than 100 explosive eruptions over the past 650,000 years. Santorini, just 8km southwest of Kolumbo is a major tourist destination visited by millions of people each year. Kolumbo therefore provides a compelling real-world case study to discuss volcanic hazards, risk awareness, and the societal relevance of geoscience research in coastal and marine settings.Designed for both classroom and outreach contexts, the 3D model and accompanying story map in five languages introduce key geoscience concepts in an intuitive and visual manner. These include seafloor mapping using multibeam bathymetry, geophysical monitoring of active volcanoes, sampling techniques at submarine volcanic sites, and the identification and assessment of volcanic hazards. The tools allow teachers to illustrate how scientists investigate submarine environments and monitor geological processes that are otherwise hidden beneath the ocean surface.The poster presentation is accompanied by a physical 3D model of Kolumbo volcano composed of four detachable blocks. These can be taken apart to reveal the internal structure of the volcano, as inferred from geophysical data, and to facilitate hands-on discussion of volcanic architecture and processes. In parallel, the digital story map presents the scientific background in an accessible and engaging format, using photographs, sketches, animations, and explanatory text.Together, the 3D model and story map aim to foster curiosity, critical thinking, and awareness of natural hazards among students, while providing teachers with physical and adaptable teaching materials. The story map is available in several languages, facilitating its use in diverse educational settings and supporting the integration of marine geosciences into Earth science education. The teaching materials have been used with great success with school classes at secondary level, for teacher training and at open days for the public.

Volcanic flank collapses represent one of the most hazardous mass-wasting processes at ocean-island volcanoes due to their potential to generate large tsunamis. Fogo volcano, located within the Cabo Verde Archipelago off the coast of West Africa, is a highly active volcanic system associated with multiple geohazards, including explosive eruptions, seismicity, landslides, and tsunamis caused by flank collapses. These processes result in the widespread submarine deposition of volcaniclastic material. However, the source mechanisms, emplacement dynamics and spatial distribution of these deposits remain poorly understood.Here we present 12 sediment cores, recovered proximal to distal from Fogo during research cruise M155 aboard RV Meteor, which contain multiple volcanogenic event layers. These layers provide archives for reconstructing mass-wasting activity and offer potential for stratigraphic correlation in marine records.This study unravels the mechanisms responsible for the formation of volcanogenic turbidites and establishes diagnostic criteria for distinguishing different types of volcaniclastic mass-transport deposits. Thereby emphasis is placed on identifying characteristic sedimentological and compositional features associated with individual event layers. We use a combined approach of structural analyses on sediment epoxy peals, quantitative sediment petrography coupled with glass-chemistry and age-modelling. This unique approach allows assigning the compositional and structural variations of volcaniclastic material to primary deposits related to flank collapses, landslides, and pyroclastic density currents from Fogo, and secondary deposits generated by other mass-wasting events and tsunami backwash in the region. Furthermore, these findings contribute to a better understanding of submarine volcanic processes and associated geohazards at ocean-island volcanoes.

We relate greenhouse gas emissions and global warming experienced over a lifetime by individual birth cohorts, resolved by world regions. We reveal outstanding geographical inequality between high- and low-emission regions corresponding to the nations of the Global North and Global South, respectively. Additionally, we highlight the inequality different birth cohorts (generations) experience regarding the burden of recent and ongoing warming temperatures as a time-delayed consequence of past emissions. We achieve precise quantification of the number of birth cohorts and populations who see a difference between Shared Socioeconomic Pathways (SSPs), emphasizing the potential for action and the chances for improvement that exist under the different scenarios. The method is designed to realistically display inequality, as it is experienced by people while motivating action and change needed to achieve emission reduction to reduce climate change and generational and geographical inequality simultaneously.

Global warming caused by anthropogenic emissions of greenhouse gases (GHG) triggers a variety of related mechanisms including rising sea levels, heatwaves, and changes in weather regimes. The effects of global warming are not spatially homogenous; Low-income countries of the global south are more severely affected than the industrialized nations of the global north. In addition, large discrepancies between birth cohorts can be observed regarding their GHG emissions as well as exposure to the effects of climate change. Globally, calls for climate justice are emerging, and courts see an increase in so-called climate cases.In a novel approach, we directly relate per-capita GHG emissions to the global temperature increase experienced by individual birth cohorts over their lifetime, in different world regions, and for different scenarios (Shared Socioeconomic Pathways; SSPs). Bridging the gap between emissions scenarios, temperature projections, and climate change impact, we quantify the geographical and generational inequality of climate change. This provides much-needed quantitative evidence to support the increasing number of climate cases and highlights the benefits, of staying within a low-emission scenario (1.5°C warming).Our results suggest a grouping of world regions into high-, and low-emission regions, revealing clear geographic patterns between the global north and south when projected onto a world map. The geographic inequality regarding per-capita emissions intensifies under SSP3 and SSP5, whereas generational inequality is largest under SSP1.We calculate an index of the ratio of GHG emissions to experienced global warming, to quantify inequality on a standardized scale, revealing the same geographic patterns and grouping of world regions observed above. Unexpectedly, the observed geographical inequality of the index is largest under SSP1 among the most recent birth cohorts, an observation that additionally pushes the debate about global justice of climate change and mitigation.

Mt Etna, Europe’s largest active volcano, is located directly on the Sicilian coastline of the Ionian Sea. In addition to frequent Strombolian eruptions, Etna’s south-eastern flank is currently sliding seawards at a rate of several centimetres per year. Over the past decade, scientists from multiple countries have intensely studied the submerged sector of the volcano and its continental margin, with their results showing that the well-known onshore flank instability proceeds far into the sea and can be measured by marine geodetic networks. Nevertheless, the relationship between volcanic activity and deformation of the continental margin is still unclear, and various scenarios – from small-scale disintegration over geological time periods to abrupt catastrophic failure – have been suggested.During RV Meteor’s expedition M178 (Nov – Dec 2021), we revisited the continental margin offshore Mt Etna and conducted dedicated repeated shallow- and deep-water multibeam surveys. In addition, several gravity cores were recovered from the prominent amphitheatre structure, intra-slope basins, and the proposed southern boundary of Mt Etna’s moving flank. We use the baseline bathymetric data, acquired during RV Meteor’s cruise M86/2 in 2011/2012, to investigate and image changes within the geomorphological and geological setting offshore Etna by comparing them with the new multibeam data. The repeated bathymetry shows minor changes compared to the baseline study, but favours the suggestion of sediment re-deposition in the proximal to distal sectors of the continental margin. Our preliminary results from the sediment record provide evidence for syn- and post sedimentary deformation, with clear indications of compressional and extensional periods at the crest of the prominent amphitheatre structure. Furthermore, sediment cores show that the southern boundary ridge, north of the Catania Canyon, hosts several heavily reworked and disintegrated sediment patches, which indicates active deformation within the intra-slope micro-basins at the crest of the ridge.The results of this project will increase our understanding of how landslides nucleate in extremely active settings such as offshore Mt Etna. Furthermore, the findings will be used to better assess the hazard potential of the sliding flank of the giant volcano and will feed into numerical modelling of the various scenarios that have been postulated for Mt Etna.