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Despite intense research by both academia and industry, the parameters controlling slope stability at continental margins are often speculated upon. Lack of core recovery and age control on failed sediments prevent the assessment of failure timing/frequency and the role of prefailure architecture as shaped by paleoenvironmental changes. This study uses an integrated chronological framework from two boreholes and complementary ultrahigh‐resolution acoustic profiling in order to assess (1) the frequency of submarine landsliding at the continental margin of NE Gela Basin and (2) the associated mechanisms of failure. Accurate age control was achieved through absolute radiocarbon dating and indirect dating relying on isotope stratigraphic and micropaleontological reconstructions. A total of nine major slope failure events have been recognized that occurred within the last 87 kyr (~10 kyr return frequency), though there is evidence for additional syndepositional, small‐scaled transport processes of lower volume. Preferential failure involves translational movement of mudflows along subhorizontal surfaces that are induced by sedimentological changes relating to prefailure stratal architecture. Along with sequence‐stratigraphic boundaries reflecting paleoenvironmental fluctuations, recovered core material suggests that intercalated volcaniclastic layers are key to the basal confinement and lateral movement of these events in the study area. Another major predisposing factor is given by rapid loading of fine‐grained homogenous strata and successive generation of excess pore pressure, as expressed by several fluid escape structures. Recurrent failure, however, requires repeated generation of favorable conditions, and seismic activity, though low if compared to many other Mediterranean settings, is shown to represent a legitimate trigger mechanism. Nine major failure events occurred at NE Gela Basin within the last 87 kyr, predominantly during conditions of sea level fall or lowstandForaminiferal records suggest additional, syndepositional processes of lower volume, counteracting the emplacement of larger landslidesPreferential failure along subhorizontal weak layers (stratigraphic boundaries and volcanoclastic layers) likely triggered by seismicity

Although submarine landslides have been studied for decades, a persistent challenge is the integration of diverse geoscientific datasets to characterize failure processes. We present a core‐log‐seismic integration study of the Tuaheni Landslide Complex to investigate intact sediments beneath the undeformed seafloor as well as post‐failure landslide deposits. Beneath the undeformed seafloor are coherent reflections underlain by a weakly‐reflective and chaotic seismic unit. This chaotic unit is characterized by variable shear strength that correlates with density fluctuations. The basal shear zone of the Tuaheni landslide likely exploited one (or more) of the low shear strength intervals. Within the landslide deposits is a widespread “Intra‐debris Reflector”, previously interpreted as the landslide's basal shear zone. This reflector is a subtle impedance drop around the boundary between upper and lower landslide units. However, there is no pronounced shear strength change across this horizon. Rather, there is a pronounced reduction in shear strength ∼10–15 m above the Intra‐debris Reflector that presumably represents an induced weak layer that developed during failure. Free gas accumulates beneath some regions of the landslide and is widespread deeper in the sedimentary sequence, suggesting that free gas may have played a role in pre‐conditioning the slope to failure. Additional pre‐conditioning or failure triggers could have been seismic shaking and associated transient fluid pressure. Our study underscores the importance of detailed core‐log‐seismic integration approaches for investigating basal shear zone development in submarine landslides. Submarine landslides move enormous amounts of sediment across the seafloor and have the potential to generate damaging tsunamis. To understand how submarine landslides develop, we need to be able to image and sample beneath the seafloor in regions where landslides have occurred. To image beneath the seafloor we generate sound waves in the ocean and record reflections from those waves, enabling us to produce “seismic images” of sediment layers and structures beneath the seafloor. We then use scientific drilling to sample the sediment layers and measure physical properties. In this study, we combine seismic images and drilling results to investigate a submarine landslide east of New Zealand's North Island. Drilling next to the landslide revealed a ∼25 m‐thick layer of sediment (from ∼75–95 m below the seafloor) that has strong variations in sediment strength and density. We infer that intervals of relatively low strength within this layer developed into the main sliding surface of the landslide. Additionally, results from within the landslide suggest that the process of landslide emplacement has induced a zone of weak sediments closer to the seafloor. Our study demonstrates how combining seismic images and drilling data helps to understand submarine landslide processes. We integrate scientific drilling data with seismic reflection data to investigate the submarine Tuaheni Landslide ComplexBasal shear zone of the landslide likely exploited a relatively low shear strength interval within an older (buried) mass transport depositLandslide emplacement seems to have induced an additional weak zone that is shallower than the interpreted base of the landslide deposit We integrate scientific drilling data with seismic reflection data to investigate the submarine Tuaheni Landslide Complex Basal shear zone of the landslide likely exploited a relatively low shear strength interval within an older (buried) mass transport deposit Landslide emplacement seems to have induced an additional weak zone that is shallower than the interpreted base of the landslide deposit

An rekonstituierten und nativen Kollagenfibrillen sowie an elastischen Fibrillen, die weitgehend frei von zelligen Bestandteilen und Kittsubstanzen präpariert waren, wurden Färbungen mit histologischen Farbstoffen und mit ph-Indikatorfarbstoffen vorgenommen. Dabei zeigten sich unerwartete Abweichungen in der Aufnahme von bekannten Farbstoffen. Diese Abweichungen müssen auf die Beeinflussung bzw. Beseitigung der Kittsubstanzen zurückgeführt werden. In einer Anzahl von Präparationen reagierten rekonstituierte Kollagenfibrillen, native Kollagenfibrillen und Elastinfibrillen gleichsinnig, so daß aus der Färbung allein keine Differenzierung möglich erschien. Versilberungen sind für Kollagen typisch und stellen echte Imprägnationen der Fasern dar. Einige Indikatorfarbstoffe gaben intensive metachromatische Färbungen. — Es wird auf die Bedeutung der angeführten Farbaufnahmeänderungen für pathologische Prozesse hingewiesen, die nach den Ergebnissen elektronenmikroskopischer Untersuchungen ohne Veränderungen des fibrillären Grundgerüstes vor sich gehen können, obwohl lichtmikroskopisch-histologisch eindeutige Veränderungen des Bindegewebes nach weisbar sind.

A transect of seafloor heat probe measurements on the Hikurangi Margin shows a significant increase of thermal gradients upslope of the updip limit of gas hydrate stability at the seafloor. We interpret these anomalously high thermal gradients as evidence for a fluid pulse leading to advective heat flux, while endothermic cooling from gas hydrate dissociation depresses temperatures in the hydrate stability field. Previous studies predict a seamount on the subducting Pacific Plate to cause significant overpressure beneath our study area, which may be the source of the fluid pulse. Double‐bottom simulating reflections are present in our study area and likely caused by uplift based on gas hydrate phase boundary considerations, although we cannot exclude a thermogenic origin. We suggest that uplift may be associated with the leading edge of the subducting seamount. Our results provide further evidence for the transient nature of fluid expulsion in subduction zones. Transient fluid expulsion causes elevated thermal gradients on the seafloor landward of the pinch out of the base of gas hydrate stabilityTemperatures within the gas hydrate stability field are depressed by endothermic cooling from gas hydrate dissociationDouble‐BSRs in the study area are likely to be caused by uplift from subduction of a seamount, which also causes fluid expulsion