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Although subaqueous slopes on active continental margins are subject to a variety of failure styles, their movement mechanisms during earthquakes remain poorly constrained. A primary explanation is that few submarine landslides have been directly sampled for detailed investigation. We have conducted a series of dynamic shear experiments on samples recovered from the base of the Tuaheni Landslide Complex, located off the east coast of the North Island of New Zealand, to explore its behaviour during earthquakes. Our experiments suggest that whilst the basal landslide sediments can be prone to liquefaction in certain conditions, this is not a likely failure mechanism at the stress states operating in the low angled shear zone at the base of this landslide system. Instead, episodic landslide movement can occur through basal sliding when pore water pressures increase sufficiently to lower the shear zone effective stress to the material failure envelope. These low effective stress conditions are most likely to be reached during earthquakes that produce large amplitude, long duration ground shaking. The observed behaviour provides a credible mechanism through which subaqueous landslides moving on low angled shear zones in similar materials may be subject to episodic movement during earthquakes without undergoing catastrophic failure.

Der interozeanische Austausch der Wassermassen südlich von Südafrika ist für die globale thermohaline Zirkulation von zentraler Bedeutung. Zunahme oder Abschwächung dieses Wassermassenaustausches führen zur Verstärkung oder Abschwächung der atlantischen Umwälzbewegung sowie zu einer entsprechenden Veränderung der Tiefenwasserbildung im Nordatlantik. Während der FS SONNE Fahrt SO-182 im April-Mai 2005 wurden mehr als 2800 Kilometer hoch auflösende refexionsseismische Daten im Transkei Becken südöstlich von Südafrika gemessen. Die Analyse zeigt, dass Nordatlantisches Tiefenwasser (NADW) und Antarktisches Bodenwasser (AABW) die Sedimentbildung in dieser Region stark beeinflussen. Die Beobachtungen zeigen weiter, dass die Ströme in dieser Region sehr variabel waren: Eine Nord-Süd-Strömung von AABW beherrschte Sedimenttransport und -absetzung im Transkei Becken vom mittlerem Miozän bis zum frühen Pliozän, gefolgt von einem Haupttransport in W-E Richtung durch NADW. Um die Sedimentanordnung und die Entwicklung der Paläozirkulation südlich von Südafrika besser zu verstehen, wird ein Ozeanzirkulationsmodell benutzt, das mit einem Sedimentmodell gekoppelt ist.Das eingesetzte Modell ist das Regional Ocean Modeling System (ROMS), das auf hydrostatischen, primitiven Gleichungen basiert. Es nutzt terrainfolgende Koordinaten in der Vertikalen und orthogonal gekrümmte Koordinaten in der Horizontalen, die je nach Fragestellung unterschiedliche Auflösung haben. Das Modell simuliert das gegenwärtige Strömungssystem in der Region südlich von Südafrika. Basierend auf dem Modell wird die Simulation der regionalen Verteilung von Sand und Silt weiterentwickelt.

Swath bathymetry images and 3.5 kHz data acquired during RV Sonne cruise 123 in autumn 1997 are the base for analysing the morphology and deformation styles of the huge Makran accretionary wedge. The continental slope off Pakistan is characterised by three morphological provinces: (a) The lower slope is built of a sequence of imbricate thrust slices which form long and narrow accretionary ridges with flanks locally as steep as 20° and between 10° and 20° on average, while the regional slope is only 1–2°, (b) the nearly flat mid-slope terrace is present in the central east part of the margin, narrows significantly towards the east, and is absent east of 63° 45' and (c) the upper slope up to the shelf has a regionally uniform slope as steep as about 8° and comprises a very rough topography with many gullies and canyons and evidence for mass wasting. Two meandering canyons crossing the entire margin down to the abyssal plain at about 63° 15'–63° 30', can be correlated with onshore rivers. They have been formed by episodic erosion through turbidity flows and are characterised by erosional and depositional portions. Sinuosity of the canyons is exclusively caused by the accretionary ridges functioning as obstacles for flow to be directly downhill. Application of Coulomb rheology to the frontal part of the Makran Wedge implies that the mid-level décollement is intrinsically extraordinary weak with a great strength contrast to the overlying sediments. Comparison with Nankai, Cascadia, and the Western Mediterranean Ridge reveals new insights in the parameters controlling the shape of an accretionary wedge and the role of a mid-level décollement.