The Link Between Upper-Slope Submarine Landslides and Mass Transport Deposits in the Hadal Trenchs

Submarine landslides occur on continental margins globally and can have devastating consequences for marine habitats, offshore infrastructure and coastal communities due to potential tsunamigenic consequences. Evaluation of the magnitude and distribution of submarine landslides is central to marine and coastal hazard planning. Despite this, there are few studies that comprehensively quantify the occurrence of submarine landslides on a margin-wide scale.&#160;We present the first margin-wide submarine landslide database along the eastern margin of New Zealand comprising >2200 landslide scars and associated mass-transport deposits. Analysis of submarine landslide distribution reveals 1) locations prone to mass-failure, 2) spatial patterns of landslide scale and occurrence, and 3) the potential preconditioning factors and triggers of mass wasting across different geologic settings.&#160;Submarine landslides are widespread on the eastern margin of New Zealand, occurring in water depths from ~300 m to ~4,000 m. Landslide scars and mass transport deposits are more prevalent, and on average larger, on the active margin, compared the passive margin. We attribute higher concentrations of landslides on the active margin to the prevalence of deforming thrust ridges, related to active margin processes including oversteepening, faulting and seamount subduction. Higher sediment supply on the northernmost active margin is also likely to be a key preconditioning factor resulting in the concentration of large landslides in this region.&#160;In general, submarine landslide scars are concentrated around canyon systems and close to canyon thalwegs. This suggests that not only does mass wasting play a major role in canyon evolution, but also that slope undercutting in canyons may be a fundamental preconditioning factor for slope failure.&#160;Results of this study offer unique insights into the spatial distribution, magnitude and morphology of submarine landslides across different geologic settings, providing a better understanding of the causative factors for mass wasting in New Zealand and around the world.&#160;

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Late Cenozoic architecture of the St. Pierre Slope

Canadian Journal of Earth Sciences ◽

10.1139/e05-059 ◽

2005 ◽

Vol 42 (11) ◽

pp. 1987-2000 ◽

Cited By ~ 11

Author(s):

David JW Piper ◽

Adam WA Macdonald ◽

Stephen Ingram ◽

Graham L Williams ◽

Curtis McCall

Keyword(s):

Mass Transport ◽

Seismic Reflection ◽

Failure Surface ◽

Late Cenozoic ◽

Grand Banks ◽

Age Model ◽

Seismic Reflection Profiles ◽

Mass Transport Deposits ◽

Bermuda Rise ◽

Upper Slope

The late Cenozoic seismic stratigraphy of the continental slope south of western Newfoundland is interpreted using new seismic reflection profiles. New MiocenePliocene biostratigraphic (palynology) age determinations on the Hermine E-94 well on the northwestern Grand Banks of Newfoundland are correlated to the study area. The Quaternary section of St. Pierre Slope is disrupted by numerous failure scarps and mass-transport deposits, but correlation from the mid- slope to the continental rise is achieved using major mass-transport deposits as markers. On the upper slope, stacked downslope-thinning wedges of acoustically incoherent sediment are interpreted as till deposits of mid- to late Pleistocene age. Sedi mentation rates in the youngest part of the succession are estimated from a 30 ka radiocarbon date 25 m below the horizon of the youngest till tongue, which is exposed on a 60 m deep failure surface. Extrapolation of sedimentation rates and comparison with dated sections on the J-Anomaly Ridge and Bermuda Rise provides a consistent interpreted age model for the till tongues that corresponds to marine isotope stages 2, 4, 6, 8, 10, and 12.

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Indonesian Throughflow as a preconditioning mechanism for submarine landslides in the Makassar Strait

Geological Society London Special Publications ◽

10.1144/sp500-2019-171 ◽

2020 ◽

Vol 500 (1) ◽

pp. 195-217 ◽

Cited By ~ 5

Author(s):

Rachel E. Brackenridge ◽

Uisdean Nicholson ◽

Benyamin Sapiie ◽

Dorrik Stow ◽

Dave R. Tappin

Keyword(s):

Mass Transport ◽

Conveyor Belt ◽

Ocean Current ◽

Indonesian Throughflow ◽

Submarine Landslides ◽

Fault Rupture ◽

The South ◽

The Pacific ◽

The Indian Ocean ◽

Mass Transport Deposits

AbstractThe Makassar Strait is an important oceanic gateway, through which the main branch of the Indonesian Throughflow (ITF) transports water from the Pacific to the Indian Ocean. This study identifies a number of moderate (>10 km3) to giant (up to 650 km3) mass transport deposits within the Makassar North Basin Pleistocene–Recent section. The majority of submarine landslides that formed these deposits originated from the Mahakam pro-delta, with the largest skewed to the south. We see clear evidence for ocean-current erosion, lateral transport and contourite deposition across the upper slope. This suggests that the ITF is acting as an along-slope conveyor belt, transporting sediment to the south of the delta, where rapid sedimentation rates and slope oversteepening results in recurring submarine landslides. A frequency for the >100 km3 failures is tentatively proposed at 0.5 Ma, with smaller events occurring at least every 160 ka. This area is therefore potentially prone to tsunamis generated from these submarine landslides. We identify a disparity between historical fault rupture-triggered tsunamis (located along the Palu-Koro fault zone) and the distribution of mass transport deposits in the subsurface. If these newly identified mass failures are tsunamigenic, they may represent a previously overlooked hazard in the region.

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Submarine mass wasting and associated tsunami risk offshore western Thailand, Andaman Sea, Indian Ocean

Natural Hazards and Earth System Science ◽

10.5194/nhess-12-2609-2012 ◽

2012 ◽

Vol 12 (8) ◽

pp. 2609-2630 ◽

Cited By ~ 8

Author(s):

J. M. Schwab ◽

S. Krastel ◽

M. Grün ◽

F. Gross ◽

P. Pananont ◽

...

Keyword(s):

Mass Transport ◽

Andaman Sea ◽

Excess Pore Pressure ◽

Western Slope ◽

Shelf Area ◽

Submarine Landslides ◽

Mass Wasting ◽

Recurrence Rates ◽

Mass Transport Deposits ◽

Water Depths

Abstract. 2-D seismic data from the top and the western slope of Mergui Ridge in water depths between 300 and 2200 m off the Thai west coast have been investigated in order to identify mass transport deposits (MTDs) and evaluate the tsunamigenic potential of submarine landslides in this outer shelf area. Based on our newly collected data, 17 mass transport deposits have been identified. Minimum volumes of individual MTDs range between 0.3 km3 and 14 km3. Landslide deposits have been identified in three different settings: (i) stacked MTDs within disturbed and faulted basin sediments at the transition of the East Andaman Basin to the Mergui Ridge; (ii) MTDs within a pile of drift sediments at the basin-ridge transition; and (iii) MTDs near the edge of/on top of Mergui Ridge in relatively shallow water depths (< 1000 m). Our data indicate that the Mergui Ridge slope area seems to have been generally unstable with repeated occurrence of slide events. We find that the most likely causes for slope instabilities may be the presence of unstable drift sediments, excess pore pressure, and active tectonics. Most MTDs are located in large water depths (> 1000 m) and/or comprise small volumes suggesting a small tsunami potential. Moreover, the recurrence rates of failure events seem to be low. Some MTDs with tsunami potential, however, have been identified on top of Mergui Ridge. Mass-wasting events that may occur in the future at similar locations may trigger tsunamis if they comprise sufficient volumes. Landslide tsunamis, emerging from slope failures in the working area and affecting western Thailand coastal areas therefore cannot be excluded, though the probability is very small compared to the probability of earthquake-triggered tsunamis, arising from the Sunda Trench.

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Formation of excess fluid pressure, sediment fluidization and mass-transport deposits in the Plio-Pleistocene Boso forearc basin, central Japan

Geological Society London Special Publications ◽

10.1144/sp477.20 ◽

2018 ◽

Vol 477 (1) ◽

pp. 255-264 ◽

Cited By ~ 3

Author(s):

Nana Kamiya ◽

Masayuki Utsunomiya ◽

Yuzuru Yamamoto ◽

Junichi Fukuoka ◽

Feng Zhang ◽

...

Keyword(s):

Mass Transport ◽

Large Scale ◽

Fluid Pressure ◽

High Porosity ◽

Submarine Landslides ◽

Forearc Basin ◽

Central Japan ◽

Pressure Interval ◽

The Stability ◽

Mass Transport Deposits

AbstractAnalyses of consolidation state, fabrics and physical properties were conducted on rock samples from the Plio-Pleistocene Boso forearc basin, central Japan. Consolidation tests identified that the trend in consolidation yield stress was systematically 8 MPa smaller than expected for the overburden from the sediment thickness of the Kazusa Group. An excess fluid pressure interval was also identified in the lower part of the basin fill, where several large-scale (several kilometres in length and several tens of metres thick) mass-transport deposits (MTDs) are intercalated. This interval is characterized by high porosity and small consolidation yield stresses, indicating that consolidation had been retarded by the excess fluid pressure. The estimated excess fluid pressure was c. 5–7 MPa. In addition, outcrop-scale fluidization and minor liquefaction features were identified within and below the high fluid pressure interval. The excess fluid pressure reduced the effective stress in the Boso forearc basin and, subsequently, the stability of the slope, allowing small tectonic events to generate submarine landslides. Therefore, the formation of these large-scale MTDs was probably related to the excess fluid-pressure generation.

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Megaclasts within mass-transport deposits: their origin, characteristics and effect on substrates and succeeding flows

Geological Society London Special Publications ◽

10.1144/sp500-2019-146 ◽

2020 ◽

Vol 500 (1) ◽

pp. 515-530 ◽

Cited By ~ 1

Author(s):

Jefferson Nwoko ◽

Ian Kane ◽

Mads Huuse

Keyword(s):

Mass Transport ◽

Seismic Reflection ◽

Radial Flow ◽

Submarine Landslide ◽

Submarine Landslides ◽

3D Seismic ◽

Seafloor Topography ◽

Basal Surface ◽

Mass Transport Deposits ◽

Substrate Influence

AbstractMegaclasts transported within submarine landslides can erode the substrate, influence the flow that transports them and, if they form seafloor topography, can influence subsequent flows and their deposits. We document grooves up to 40 km long formed by megaclasts carried in submarine landslides that scoured tens of metres deep into the contemporaneous substrate of the deep-water Taranaki Basin, New Zealand. A 1925 km2 3D seismic reflection survey records six mass transport deposits (MTDs) interbedded with turbidites. Here, we focus on three MTDs, labelled A (oldest), B and C (youngest). MTD-A features megaclasts that internally have coherent parallel strata, and formed striations 4–15 km long and 2–3 km wide, with protruding megaclasts that are onlapped by younger sediments. The seafloor expression of these megaclasts partially obstructed the submarine landslide that created MTD-B. MTD-B contains megaclasts that incised through the rugose topography of the underlying MTD-A, and formed divergent grooves on the basal surface of MTD-B (8–40 km long and 200–250 m wide), which suggest radial flow expansion where flows exited topographic confinement. MTD-C features grooves 2–6 km long and 100–200 m wide that terminate at megaclasts and which internally are characterized of highly deformed reflectors surrounded by a chaotic matrix. This study directly links megaclasts to the grooves they form, and demonstrates that markedly different styles of scouring and resultant grooves can occur in closely related MTDs.

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