Tectonic and geomorphic controls on the distribution of submarine landslides across active and passive margins, eastern New Zealand

2019 ◽  
Vol 500 (1) ◽  
pp. 477-494 ◽  
Author(s):  
S. J. Watson ◽  
J. J. Mountjoy ◽  
G. J. Crutchley
Keyword(s):  
New Zealand ◽  
Slope Failure ◽  
Submarine Landslide ◽  
Passive Margin ◽  
Continental Margins ◽  
Submarine Landslides ◽  
Mass Wasting ◽  
Active Margin ◽  
Passive Margins ◽  
Marine Habitats

AbstractSubmarine landslides occur on continental margins globally and can have devastating consequences for marine habitats, offshore infrastructure and coastal communities due to potential tsunamigenesis. Therefore, understanding landslide magnitude and distribution is central to marine and coastal hazard planning.We present the first submarine landslide database for the eastern margin of New Zealand comprising >2200 landslides occurring in water depths from c. 300–4000 m. Landslides are more prevalent and, on average, larger on the active margin compared with the passive margin. We attribute higher concentrations of landslides on the active margin to tectonic processes including uplift and oversteepening, faulting and seamount subduction. 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 canyon-forming processes may provide preconditioning factors for slope failure.Results of this study offer unique insights into the spatial distribution, magnitude and morphology of submarine landslides across different geological settings, providing a better understanding of the causative factors for mass wasting in New Zealand and around the world.

Tectonic and geomorphic controls on the distribution of submarine landslides across active and passive margins, eastern New Zealand

2020 ◽  
Author(s):  
Sally Watson ◽  
Joshu Mountjoy ◽  
Gareth Crutchley
Keyword(s):  
New Zealand ◽  
Mass Transport ◽  
Submarine Landslide ◽  
Sediment Supply ◽  
Submarine Landslides ◽  
Mass Wasting ◽  
Active Margin ◽  
Eastern Margin ◽  
Marine Habitats ◽  
Mass Transport Deposits

<p>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.</p><p> </p><p>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.</p><p> </p><p>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.</p><p> </p><p>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.</p><p> </p><p>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.</p><p> </p>

scholarly journals Deep submarine landslide contribution to the 2010 Haiti earthquake tsunami

2020 ◽  
Vol 20 (7) ◽  
pp. 2055-2065
Author(s):  
Adrien Poupardin ◽  
Eric Calais ◽  
Philippe Heinrich ◽  
Hélène Hébert ◽  
Mathieu Rodriguez ◽  
...  
Keyword(s):  
Slope Failure ◽  
Tide Gauge ◽  
Strike Slip ◽  
Submarine Landslide ◽  
Secondary Source ◽  
Submarine Landslides ◽  
Haiti Earthquake ◽  
Southern Coast ◽  
Ground Acceleration ◽  
The North

Abstract. The devastating Mw 7.1 Haiti earthquake in 2010 was accompanied by local tsunamis that caused fatalities and damage to coastal infrastructure. Some were triggered by slope failures of river deltas in the close vicinity of the epicenter, while others, 30 to 50 km to the north across the Bay of Gonâve, are well explained by the reverse component of coseismic ground motion that accompanied this mostly strike-slip event. However, observations of run-up heights up to 2 m along the southern coast of the island at distances up to 100 km from the epicenter, as well as tide gauge and DART buoy records at distances up to 600 km from the epicenter, have not yet received an explanation. Here we demonstrate that these observations require a secondary source, most likely a submarine landslide. We identify a landslide scar 30 km from the epicenter off the southern coast of Haiti at a depth of 3500 m, where ground acceleration would have been sufficient to trigger slope failure in soft sediments. This candidate source, 2 km3 in volume, matches observations remarkably well assuming that the sediment collapse obeys a viscous flow with an initial apparent viscosity of 2×105 Pa s. Although that particular source cannot be proven to have been activated in 2010, our results add to a line of evidence that earthquake-triggered submarine landslides can cause significant tsunamis in areas of strike-slip tectonic regime.

Slope failure and mass transport processes along the Queen Charlotte Fault Zone, western British Columbia

2018 ◽  
Vol 477 (1) ◽  
pp. 85-106 ◽  
Author(s):  
H. Gary Greene ◽  
J. Vaughn Barrie ◽  
Daniel S. Brothers ◽  
James E. Conrad ◽  
Kim Conway ◽  
...  
Keyword(s):  
Continental Slope ◽  
Fault Zone ◽  
Slope Failure ◽  
Transport Processes ◽  
North American Plate ◽  
Submarine Landslides ◽  
Mass Wasting ◽  
The North ◽  
Transform Margin ◽  
Seismic Reflection Profiles

AbstractMultibeam echosounder (MBES) images, 3.5 kHz seismic-reflection profiles and piston cores obtained along the southern Queen Charlotte Fault Zone are used to map and date mass-wasting events at this transform margin – a seismically active boundary that separates the Pacific Plate from the North American Plate. Whereas the upper continental slope adjacent to and east (upslope) of the fault zone offshore of the Haida Gwaii is heavily gullied, few large-sized submarine landslides in this area are observed in the MBES images. However, smaller submarine seafloor slides exist locally in areas where fluid flow appears to be occurring and large seafloor slides have recently been detected at the base of the steep continental slope just above its contact with the abyssal plain on the Queen Charlotte Terrace. In addition, along the subtle slope re-entrant area offshore of the Dixon Entrance shelf bathymetric data suggest that extensive mass wasting has occurred in the vicinity of an active mud volcano venting gas. We surmise that the relative lack of submarine slides along the upper slope in close proximity to the Queen Charlotte Fault Zone may be the result of seismic strengthening (compaction and cohesion) of a sediment-starved shelf and slope through multiple seismic events.

The nature of small to medium earthquakes along the Eastern Mediterranean passive continental margins, and their possible relationships to landslides and submarine salt-tectonic-related shallow faults

2018 ◽  
Vol 477 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Oded Katz ◽  
Yariv Hamiel
Keyword(s):  
Continental Slope ◽  
Slope Failure ◽  
Eastern Mediterranean ◽  
Hazard Analysis ◽  
Focal Depth ◽  
Seismic Source ◽  
Continental Margins ◽  
Submarine Landslides ◽  
Seismic Origin ◽  
First Time

AbstractWe analysed here, for the first time, 278 small to medium earthquakes that have occurred since 1985 along a 200 km section of the Levant passive continental margins, offshore Israel. The earthquakes are spatially overlapping with numerous submarine landslides and thin-skinned salt-tectonic-related faults scarps, bisecting the continental slope. Thus, we focus on the genetic relationship between the earthquakes, the faults and the landslides.We found that a subgroup of 55 earthquakes is spatially overlapping with the marine extension of the Carmel Fault and thus might be of tectonic origin. A second subgroup, hosting approximately 130 earthquakes, is spatially overlapping with the longshore salt-tectonic-related submarine faults. However, due to the non-shallow focal depth of most of these earthquakes, salt tectonics was ruled out as their possible seismic origin. Thus, the seismic source for theanalysed earthquakes is yet to be revealed.We further found that the observed medium earthquakes (M > 4) have a calculated reoccurrence time of more than 10 years and they are capable of inducing submarine slope failure within the studied area. Hence, they might play a role in submarine mass-wasting processes along the studied continental slope, and must now be considered in future hazard analysis.

Geological and tectonic controls on morphometrics of submarine landslides of the Spanish margins

2020 ◽  
Vol 500 (1) ◽  
pp. 495-513 ◽  
Author(s):  
Ricardo León ◽  
Roger Urgeles ◽  
Raul Pérez-López ◽  
Emilio Payo ◽  
Amanda Vázquez-Izquierdo ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Deep Ocean ◽  
Submarine Landslide ◽  
Geographical Information ◽  
Continental Margins ◽  
Submarine Landslides ◽  
Slope Failures ◽  
Average Slope ◽  
Volcanic Islands ◽  
Geomorphological Analysis

AbstractA geomorphological analysis of the submarine landslides geographical information system catalogue of the Geological Survey of Spain has revealed three main groups of submarine landslides associated with (1) deep-ocean seamount ridges (extinct spreading centres), (2) volcanic islands and (3) continental margins. These three groups have statistically significant morphometric differences, as determined from analysis of variance (ANOVA) and Tukey's HSD Tests, in total length (runout), total area, maximum deposit width and bathymetric depth. Volcanic island-related slope failures affect larger areas of the seafloor and their headwall escarpments often extend above sea-level. Slope failures associated with seamount ridges are the deepest, between 3500 and 5500 m, and display relatively high width-to-length ratios. Finally, landslides on continental margins show two sub-groups. Landslides on tectonically controlled margins have smaller runouts and total area and larger average slope gradients than margins where tectonic controls are limited. These results demonstrate that submarine landslide morphology is strongly controlled by the geological-tectonic setting.

Birthdate for the Coronation paleocean: age of initial rifting in Wopmay orogen, CanadaThis article is one of a series of papers published in this Special Issue on the theme of Geochronology in honour of Tom Krogh.

2011 ◽  
Vol 48 (2) ◽  
pp. 281-293 ◽  
Author(s):  
Paul F. Hoffman ◽  
Samuel A. Bowring ◽  
Robert Buchwaldt ◽  
Robert S. Hildebrand
Keyword(s):  
Detrital Zircon ◽  
Hanging Wall ◽  
Passive Margin ◽  
Pyroclastic Rock ◽  
Continental Margins ◽  
Ionization Mass ◽  
Slave Craton ◽  
Passive Margins ◽  
Igneous Zircon ◽  
The Mean

The 1.9 Ga Coronation “geosyncline” to the west of Slave craton was among the first Precambrian continental margins to be identified, but its duration as a passive margin has long been uncertain. We report a new U–Pb (isotope dilution – thermal ionization mass spectrometry (ID–TIMS)) 207Pb/206Pb date of 2014.32 ± 0.89 Ma for zircons from a felsic pyroclastic rock at the top of the Vaillant basalt, which underlies the passive margin sequence (Epworth Group) at the allochthonous continental slope. A sandstone tongue within the basalt yields Paleoproterozoic (mostly synvolcanic) and Mesoarchean detrital zircon dates, of which the latter are compatible with derivation from the Slave craton. In contrast, detrital zircon grains from the Zephyr arkose in the accreted Hottah terrane have Paleoproterozoic and Neoarchean dates. The latter cluster tightly at 2576 Ma, indistinguishable from igneous zircon dates reported here from the Badlands granite, which is faulted against the Vaillant basalt and underlying Drill arkose. We interpret these data to indicate that Badlands granite belongs to the hanging wall of the collisional geosuture between Hottah terrane and the Slave margin, represented by the Drill–Vaillant rift assemblage. If 2014.32 ± 0.89 Ma dates the rift-to-drift transition and 1882.50 ± 0.95 Ma (revised from 1882 ± 4 Ma) the arrival of the passive margin at the trench bordering the Hottah terrane, the duration of the Coronation passive margin was ∼132 million years, close to the mean age of extinct Phanerozoic passive margins of ∼134 million years (see Bradley 2008).

scholarly journals Are submarine landslides an underestimated hazard on the western North Atlantic passive margin?

Geology ◽  
2019 ◽  
Vol 47 (9) ◽  
pp. 848-852 ◽  
Author(s):  
Alexandre Normandeau ◽  
D. Calvin Campbell ◽  
David J.W. Piper ◽  
Kimberley A. Jenner
Keyword(s):  
North Atlantic ◽  
Late Holocene ◽  
Detailed Examination ◽  
Submarine Landslide ◽  
Passive Margin ◽  
Submarine Landslides ◽  
Eastern Canada ◽  
Grand Banks ◽  
Landslide Event ◽  
Slope Instabilities

AbstractThe western North Atlantic passive margin is considered relatively stable, with few slope instabilities recognized during the Holocene. However, new multibeam bathymetry mapping and sediment core acquisition off eastern Canada indicate that previously unidentified, large, submarine landslide events occurred during the Late Holocene, between 4 and 1.5 ka. The recognition of these new gravitational events, in addition to the well-known C.E. 1929 Grand Banks earthquake-induced landslide, indicates that approximately one large landslide event per 1000 years has occurred offshore eastern Canada within the past 4000 years, a much shorter recurrence interval than hitherto reported. This Late Holocene recurrence rate is also similar to active margins around the world and is likely due to the under-consolidation and resultant instability of Scotian Slope sediments attributable to high glacial sedimentation rates. The discovery of these new Late Holocene landslides was made possible through detailed examination of cores recovered from the lower slope. These results demonstrate that submarine landslide hazard has been underestimated on the western North Atlantic margin—home to significant submarine infrastructure and proximal to a large coastal population.

scholarly journals Early extensional detachments in a contractional orogen: coherent, map-scale, submarine slides (mass transport complexes) on the outer slope of an Ediacaran collisional foredeep, eastern Kaoko belt, Namibia

2016 ◽  
Vol 53 (11) ◽  
pp. 1177-1189 ◽  
Author(s):  
Paul F. Hoffman ◽  
Eric J. Bellefroid ◽  
Benjamin W. Johnson ◽  
Malcolm S.W. Hodgskiss ◽  
Daniel P. Schrag ◽  
...  
Keyword(s):  
Large Scale ◽  
Sedimentary Facies ◽  
Passive Margin ◽  
Continental Margins ◽  
Submarine Landslides ◽  
Base Level ◽  
Basin Scale ◽  
Kaoko Belt ◽  
Map Scale ◽  
Orogenic Belts

The existence of coherent, large-scale, submarine landslides on modern continental margins implies that their apparent rarity in ancient orogenic belts is due to non-recognition. Two map-scale, coherent, pre-orogenic, normal-sense detachment structures of Ediacaran age are present in the Kaoko belt, a well-exposed arc–continent collision zone in northwestern Namibia. The structures occur within the Otavi Group, a Neoproterozoic carbonate shelf succession. They are brittle structures, evident only through stratigraphic omissions of 400 m or more, that ramp down to the west with overall ramp angles of 1.1° and 1.3° with respect to stratigraphic horizons. The separations of matching footwall and hangingwall stratigraphic cut-offs require horizontal translations >20 km for each detachment. One of the detachments is remarkably narrow (5 km) in the up-dip direction, just one fourth of its translation. The other detachment is stratigraphically dated at the shelf–foredeep transition, when the passive margin was abortively subducted westward, in the direction of submarine sliding. Trenchward sliding on the foreslope occurred concurrently with deep karstification of the autochthonous carbonate succession to the east, presumably due to forebulge uplift and (or) conjectural basin-scale base-level fall. We expect that similar detachments exist in other orogenic belts, and failure to recognize them can lead to misinterpretations of stratigraphy, sedimentary facies, and paleogeography.

scholarly journals Deep Submarine Landslide Contribution to the 2010 Haiti Earthquake Tsunami

2020 ◽  
Author(s):  
Adrien Poupardin ◽  
Eric Calais ◽  
Philippe Heinrich ◽  
Hélène Hébert ◽  
Mathieu Rodriguez ◽  
...  
Keyword(s):  
Slope Failure ◽  
Tide Gauge ◽  
Strike Slip ◽  
Submarine Landslide ◽  
Secondary Source ◽  
Submarine Landslides ◽  
Haiti Earthquake ◽  
Southern Coast ◽  
Ground Acceleration ◽  
The North

Abstract. The devastating Mw 7, 2010, Haiti earthquake was accompanied by local tsunamis that caused fatalities and damage to coastal infrastructure. Some were triggered by slope failures of river deltas in close vicinity of the epicenter, while others, 30 to 50 km to the north across the Bay of Gonâve, are well explained by the reverse component of coseismic ground motion that accompanied this mostly strike-slip event. However, observations of run-up heights up to 2 m along the southern coast of the island at distances up to 100 km from the epicenter, as well as tide gauge and DART buoy records at distances up to 600 km from the epicenter have not yet received an explanation. Here we demonstrate that these observations require a secondary source, most likely a submarine landslide. We identify a landslide scar 30 km from the epicenter off the southern coast of Haiti at a depth of 3500 m, where ground acceleration would have been sufficient to trigger slope failure in soft sediments. This candidate source, 2 km3 in volume, matches observation remarkably well assuming that the sediment collapse obeys a viscous flow with an initial apparent viscosity of 2 × 105 Pa s. Although that particular source cannot be proven to have been activated in 2010, our results add to a line of evidence that earthquake-triggered submarine landslides can cause significant tsunamis in areas of strike-slip tectonic regime.

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