Submarine landslide geomorphology, US continental slope

McAdoo, Brian G.; Pratson, Lincoln F.; Orange, Daniel L.

doi:10.1016/s0025-3227(00)00050-5

Cited by 410 publications

(342 citation statements)

References 22 publications

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“…However, their near-circular shape, low regional slope (0.1-1.5°), and their interior morphology are atypical for slump features [McAdoo et al, 2000]. Bottom currents may, however, have modified GEF morphology and could account for the northeast gap in the largest pockmarks.…”

Section: Formation Mechanisms Of Gef'smentioning

confidence: 99%

Gas escape features off New Zealand: Evidence of massive release of methane from hydrates

Davy

Pecher

Wood

et al. 2010

Geophysical Research Letters

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Multibeam swath bathymetry data from the southwest margin of the Chatham Rise, New Zealand, show gas release features over a region of at least 20,000 km2. Gas escape features, interpreted to be caused by gas hydrate dissociation, include an estimated a) 10 features, 8–11 km in diameter and b) 1,000 features, 1–5 km in diameter, both at 800–1,100 m water depth. An estimated 10,000 features, ∼150 m in diameter, are observed at 500–700 m water depth. In the latter depth range sub‐bottom profiles show similar gas escape features (pockmarks) at disconformities interpreted to mark past sea‐level low stands. The amount of methane potentially released from hydrates at each of the largest features is ∼7*1012 g. If the methane from a single event at one 8–11 km scale pockmark reached the atmosphere, it would be equivalent to ∼3% of the current annual global methane released from natural sources into the atmosphere.

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Section: Formation Mechanisms Of Gef'smentioning

confidence: 99%

Gas escape features off New Zealand: Evidence of massive release of methane from hydrates

Davy

Pecher

Wood

et al. 2010

Geophysical Research Letters

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“…2b), thus indicating that steepness is not a major parameter controlling the initiation of slides in the study area. The minor effect of the slope gradient on the initiation of slides have been mentioned previously in the literature (Hampton et al 1996;Booth et al 1993;McAdoo et al 2000;Canals et al, 2004;Sultan et al 2004;Hühnerbach and Masson 2004;Lastras et al 2006). …”

Section: Characteristics and Setting Of Slidesmentioning

confidence: 57%

Quantifying the role of sandy–silty sediments in generating slope failures during earthquakes: example from the Algerian margin

Dan

Sultan

Savoye

et al. 2008

Int J Earth Sci (Geol Rundsch)

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Abstract:The Algerian margin is a seismically active region, where during the last century, several large magnitude earthquakes took place. This study combines geotechnical and sedimentological data with numerical modelling to quantitatively assess the present-day slope stability of the Algerian margin. Geotechnical laboratory tests, such as cyclic triaxial tests, oedometric tests and vane shear tests were carried out on sediment cores collected on the study area. The liquefaction potential of a sediment column located about 30 km from the Boumerdès earthquake epicentre of 21st May 2003 was evaluated theoretically for an earthquake of M w = 6.8. We show that thin sand and silt beds such as those described on recovered sediment cores are the main cause of sediment deformation and liquefaction during earthquakes. Numerical calculations showed that the slope failure may occur during an earthquake characterised by a PGA in excess of 0.1g, and also that, under a PGA of 0.2g liquefaction could be triggered in shallow silty-sandy deposits. Moreover, comparison of the predicted slope failure with failure geometries inferred from seafloor morphology showed that earthquakes and subsequent mass movements could explain the present-day morphology of the study area.

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“…[36] When comparing the low recurrence rate of the large PGA-triggered landslides to other areas, similar conclusions were drawn from studies investigating submarine landslides along active continental margins [e.g., McAdoo et al, 2000;Camerlenghi et al, 2010]. At accretionary and erosive subduction margins fore-arc slopes also show large infrequent landslides because of tectonically exhumed sediments that tend to be overconsolidated, therefore bearing a high shear resistance and requiring large earthquakes as triggers Camerlenghi et al, 2010].…”

Section: Conclusion and General Implicationsmentioning

confidence: 67%

Slope failure repetition in active margin environments: Constraints from submarine landslides in the Hellenic fore arc, eastern Mediterranean

et al. 2010

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[1] It has been shown that submarine landslides can occur less frequently at subduction zone fore arcs despite the general expectation of extensive slope failures from high neotectonic activity in active margin settings. The Hellenic subduction zone, Greece, represents an example where modern evidence for slope failure is scarce. Taking the deeper parts of the fore-arc basin into account, however, a sequence of massive landslide deposits is found at recurrence intervals of approximately 250 ± 70 ka. Given high seismicity in the fore-arc area, this rate of slope failure appears to be low. In order to improve our understanding on the relationship between low landslide recurrence rates and the frequency and settings of the required trigger mechanism, we here assess the mechanical behavior of the slope sediment cover during instability scenarios. Seismic profiles and geotechnical measurements from cores of midsize landslides found on the northeastern Cretan midslope are used to backanalyze slope destabilization in one-dimensional, infinite slope models for static conditions as well as for the case of seismic loading. Results reveal that today only critically steepened parts of the Cretan slope can fail from high loading stresses of peak ground acceleration (PGA) of 37%g, maybe up to ≥64%g. We further deduce that long-term tectonic processes are important preconditioning factors controlling an occasional development of critically inclined slope parts. Therefore, the impact of seismic triggers is strongly limited in time and space: For an initially stable slope, the critical seismic intensity to trigger failure is being reduced with increasing tectonically controlled steepening of the slope through time, until an earthquake is sufficient to trigger a large landslide. Before that, the slope rather gets more resistant, because smaller PGA may rather result in dynamic compaction (seismic strengthening). Our findings imply that low frequencies of landslides in the Hellenic fore arc are not in conflict with high seismicity in this region, because seismic loading is only sufficient to trigger major collapses of a generally shear-resistant "cohesive" slope (increasing with time due to seismic strengthening) if long-term tectonic movement provides a critical steepening. This may explain the relatively scarce occurrence of large submarine landslides in this and similar tectonically active environments.Citation: Strozyk, F., M. Strasser, A. Förster, A. Kopf, and K. Huhn (2010), Slope failure repetition in active margin environments: Constraints from submarine landslides in the Hellenic fore arc, eastern Mediterranean,

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Submarine landslide geomorphology, US continental slope

Cited by 410 publications

References 22 publications

Gas escape features off New Zealand: Evidence of massive release of methane from hydrates

Gas escape features off New Zealand: Evidence of massive release of methane from hydrates

Quantifying the role of sandy–silty sediments in generating slope failures during earthquakes: example from the Algerian margin

Slope failure repetition in active margin environments: Constraints from submarine landslides in the Hellenic fore arc, eastern Mediterranean

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