Description: Water column raw data using the ship's own Kongsberg EM 122 multibeam echosounder was recorded on 20 days between 2019-08-06 and 2019-09-03 RV SONNE cruise SO269 in the South China Sea. The data are archived at the Federal Maritime and Hydrographic Agency of Germany (Bundesamt für Seeschifffahrt und Hydrographie, BSH) and provided to PANGAEA database for data curation and publication. Ancillary sound velocity profiles (SVP) files from the cruise are archived at the BSH and added to the corresponding multibeam raw dataset https://doi.org/10.1594/PANGAEA.945591 This publication is conducted within the efforts of the German Marine Research Alliance in the core area 'Data management and Digitalization' (Deutsche Allianz Meeresforschung, DAM).

Description: Multibeam bathymetry raw data using the ship's own Kongsberg EM 122 multibeam echosounder was not continuously recorded during RV SONNE cruise SO269. Data was recorded on 13 days between 2019-08-05 and 2019-08-28. This dataset contains a survey in the South China Sea. The approximate average depth of the entire dataset is around 2300m. The data are archived at the Federal Maritime and Hydrographic Agency of Germany (Bundesamt für Seeschifffahrt und Hydrographie, BSH) and provided to PANGAEA database for data curation and publication. Ancillary sound velocity profiles (SVP) files from the cruise are archived at the BSH, thus SVP files are added to this dataset. However, also data analysis of the multibeam raw data revealed that SVP has been changed during the survey. This publication is conducted within the efforts of the German Marine Research Alliance in the core area 'Data management and Digitalization' (Deutsche Allianz Meeresforschung, DAM). Data are unprocessed and therefore contains incorrect depth measurements (artifacts) without further processing. Note that refraction errors can be expected due to the lack of proper SVP. Overall, it appears that the data quality is rather good since the gridded hillshade data showed relatively few obstacles. Data can be processed e.g. with the open source software package MB-System (Caress, D. W., and D. N. Chayes, MB-System: Mapping the Seafloor, http://www.mbari.org/products/research-software/mb-system/, 2022).

Description: Multibeam bathymetry raw data using the ship's own Kongsberg EM 710 multibeam echosounder was not continuously recorded during RV SONNE cruise SO269. Data was recorded on 20 days between 2019-08-06 and 2019-09-03. This dataset contains a survey in the South China Sea. The approximate average depth of the entire dataset is around 300m. The data are archived at the Federal Maritime and Hydrographic Agency of Germany (Bundesamt für Seeschifffahrt und Hydrographie, BSH) and provided to PANGAEA database for data curation and publication. Ancillary sound velocity profiles (SVP) files from the cruise are archived at the BSH, thus SVP files are added to this dataset. However, also data analysis of the multibeam raw data revealed that SVP has been changed during the survey. This publication is conducted within the efforts of the German Marine Research Alliance in the core area 'Data management and Digitalization' (Deutsche Allianz Meeresforschung, DAM). Data are unprocessed and therefore contains incorrect depth measurements (artifacts) without further processing. Note that refraction errors can be expected due to the lack of proper SVP. Overall, it appears that the data quality is rather good since the gridded hillshade data showed relatively few obstacles. Data can be processed e.g. with the open source software package MB-System (Caress, D. W., and D. N. Chayes, MB-System: Mapping the Seafloor, http://www.mbari.org/products/research-software/mb-system/, 2022).

Description: The Ionian Sea between Sicily and Calabria is known for its complex geological setting, as it is located at the convergence zone of the African and Eurasian plates. The seismogenic potential in this region is manifested by several high magnitude and disastrous earthquakes like the 1908 Messina Earthquake. Furthermore, the area is affected by intense volcanism like the Aeolian Island volcanos in the Tyrrhenian Sea and Europe’s largest active volcano, Mt Etna, sitting directly at the eastern coast of Sicily. During the last years, the possible presence of Subduction Tear Edge Propagator faults (STEP-faults) has been heavily debated. The main candidates for these faults are the Ionian Fault in the Northeast and the Alfeo-Etna Fault in the Southwest of the working area between Sicily and Calabria. Nevertheless, only little is known about near seafloor deformation zones and sedimentary processes in the Ionian Sea directly south of the Messina Strait. In order to obtain a better understanding of the sedimentary processes and the role of tectonics in the region, a new high-resolution 2D reflection seismic dataset was acquired during POS496 cruise during March – April 2016. In combination with existing additional seismic and bathymetric data, we mapped the area in terms of sedimentary and tectonic systems between Sicily and Calabria south of Messina Strait. The overall aim is to understand the relationship between tectonics and sedimentary processes in this complex geological area. The entire working area shows a variety of submarine channels, evolving from the central Messina Strait Canyon. In addition, large syn-tectonic south-north trending half grabens and sedimentary basins are imaged. The basins are filled by turbiditic- and contouritic deposits. Furthermore, several anticlines and negative flower structures were identified. We interpret these tectonic lineaments as the surface expression of deeply rooted transpressiveand transtensional fault systems. These fault systems with large strike-slip components could be near surface indicators for the proposed STEP Faults in the region. Not all morphological features like canyons/channels and structural heights follow significant tectonic lineaments. This indicates that some sedimentary features are decoupled from tectonics and are rather the expression of long lasting sedimentary processes like turbidity currents, mass transport events and bottom current activity.

Description: The relatively fast and continuous build-up of a volcanic island can lead to an unstable edifice which might be prone to collapse under its own weight. Evidence for major flank-collapse events are found offshore a wide range of volcanic islands, suggesting this phenomenon to be a common process with potentially disastrous consequences as they can generate devastating tsunamis. Fogo Island is situated in the southeastern part of the Cape Verdean Archipelago, about 700 km west of Dakar, NW Africa. During the Monte Amarelo event, approx. 73,000 years ago, its subaerial eastern flank collapsed into the ocean, triggering a mega tsunami with run-up heights of up to 270 m as witnessed by dated tsunami deposits found on the neighboring island of Santiago, ~60 km eastwards from Fogo. Whether the collapse occurred in a single event or multiple phases remains unknown and a volume estimation of the collapse difficult and uncertain as the base of the deposit could not have been captured offshore before. Such information, however, is essential for modeling a more reliable tsunami generation scenario. During the research cruise M155 in June 2019, a set of high-resolution multichannel (MSC) reflection seismic data along with hydroacoustic data was gathered. In most of the MSC profiles, a common reflector is identifiable and regarded as the base of the Monte Amarelo deposit, allowing the reassessment of the volume of failed and remobilized material. In addition, prominent internal reflectors within the chaotic facies defining the Monte Amarelo deposit in the MSC data, strongly suggest the collapse might have happened in multiple phases. Such observation is critical to better assess tsunami modeling associated with volcanic flank collapses.

Description: Im Ionischen Meer, südlich vom italienischen Festland und östlich Siziliens, liegt eine der komplexesten tektonisch aktiven Regionen der Welt. Die Kombination aus der hohen Bevölkerungsdichte an den umliegenden Küsten und dem regelmäßigen Auftreten von Erdbeben hoher Magnitude und nachfolgenden Tsunamis birgt das Risiko desaströser Folgen beim Eintritt eines solchen Ereignisses. Es ist deshalb von essentieller Bedeutung für den Umgang mit Naturkatastrophen und ihren Konsequenzen, die beteiligten tektonische und sedimentären Prozesse dieser Region im Detail zu untersuchen. Während der Expedition POS496 auf dem Forschungsschiff Poseidon im März und April 2016 wurden hochauflösende Mehrkanal reflektionsseismische Daten aufgenommen. Mit Hilfe von vorhandenen Daten, die während der Ausfahrt MS86/2 aufgenommen wurden, war es möglich einen regionalen Überblick über das Untersuchungsgebiet zu erhalten. Das Ziel ist es, tektonische und sedimentäre Strukturen zu lokalisieren, um eine morphotektonische Karte des Untersuchungsgebietes zu erstellen. Einige der wesentlichen sedimentären Strukturen, die auftreten, sind ein großes Sedimentbecken entlang des Malta Escarpment, ein Sedimentwellenfeld und zwei große Kanäle, von denen einer den unteren Teil des Messina Strait Canyons darstellt. Mehrere NW-SO ausgerichtete Antiklinen, die als Blattverschiebungen identifiziert werden können, könnten Oberflächenerscheinungen eines Subduction-Tear-Edge-Propagator-Faults sein. Ein an der Oberfläche im Durchmesser 6 km großes, rundes Basement Hoch wird als alter Seamount interpretiert, dessen Herkunft unklar bleibt.

Description: Volcanic islands are known to be a source of many natural hazards associated with active volcanism. The processes leading to the instability of their flanks, however are less well understood. The movement of an instable volcanic flank occurs in either or both of two ways; slow sliding of several cm per year (i.e. Etna, Italy) and/or the catastrophic collapse of a large portion of the edifice (i.e. Anak Krakatau, Indonesia). The conditions and precursors leading to such events are often unknown. The limited availability of high-resolution bathymetry data especially at the coast is often restricting the quantitative geomorphological investigation to the subaerial part of the volcanic island. It is essential, however, to include the entire volcanic edifice as instability affects the volcano from summit to seafloor. In this study, we test whether and in which way, the morphology of the volcanic edifice affects its instability. We combine openly available high-resolution bathymetric and topographic grids (50-150m grid spacing) to create shoreline-crossing DEMs of volcanic islands in four areas (archipelagos of Hawaii, Canaries, Mariana Islands and South Sandwich Islands). Morphological parameters, such as area, volume, height from seafloor, slope etc. of the entire volcanic edifice are derived from the DEM grids and inserted into a database. The statistical analysis of this data combined with the history of flank failure will shed light on the influence the morphology of a volcanic island has on its instability. This will lead to a better understanding of the processes involved in the movement of instable volcanic flanks.