Modelling the 1929 Grand Banks slump and landslide tsunami

AbstractOn 18 November 1929, an Mw 7.2 earthquake occurred south of Newfoundland, displacing >100 km3 of sediment volume that evolved into a turbidity current. The resulting tsunami was recorded across the Atlantic and caused fatalities in Newfoundland. This tsunami is attributed to sediment mass failure because no seafloor displacement due to the earthquake has been observed. No major headscarp, single evacuation area nor large mass transport deposit has been observed and it is still unclear how the tsunami was generated. There have been few previous attempts to model the tsunami and none of these match the observations. Recently acquired seismic reflection data suggest that rotational slumping of a thick sediment mass may have occurred, causing seafloor displacements up to 100 m in height. We used this new information to construct a tsunamigenic slump source and also carried out simulations assuming a translational landslide. The slump source produced sufficiently large waves to explain the high tsunami run-ups observed in Newfoundland and the translational landslide was needed to explain the long waves observed in the far field. However, more analysis is needed to derive a coherent model that more closely combines geological and geophysical observations with landslide and tsunami modelling.

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Application of section-balancing techniques to deep seismic reflection data from offshore eastern Canada: preliminary observations

Canadian Journal of Earth Sciences ◽

10.1139/e90-045 ◽

1990 ◽

Vol 27 (4) ◽

pp. 494-500 ◽

Cited By ~ 2

Author(s):

M. C. Dentith ◽

J. Hall

Keyword(s):

Seismic Reflection ◽

Hanging Wall ◽

Shear Zones ◽

Ductile Deformation ◽

Eastern Canada ◽

Seismic Reflection Data ◽

Deep Seismic Reflection ◽

Grand Banks ◽

Jeanne D'arc Basin ◽

Reflection Data

The application of section-balancing techniques to the analysis of deep seismic sections requires account be taken of isostasy and ductile-deformation processes. Structures imaged by deep seismic reflection profiling across the southern Grand Banks, offshore eastern Canada, are analyzed in this way. Correlations of dipping events in the deep crust, interpreted as shear zones, with faults recognized in the shallow part of the section are tested by attempting to restore the sections to their undeformed state by reversing the displacements on the faults. This process tests the geometric compatibility of the interpreted fault and the structures in its hanging wall. Our models suggest that the faults bounding the Whale and Horseshoe basins detach at the Mohorovičić discontinuity. In contrast, the fault bounding the Jeanne d'Arc Basin detaches within the lower crust.

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Proterozoic orogens of the northeastern Canadian Shield: new information from the Lithoprobe ECSOOT crustal reflection seismic survey

Canadian Journal of Earth Sciences ◽

10.1139/e95-093 ◽

1995 ◽

Vol 32 (8) ◽

pp. 1119-1131 ◽

Cited By ~ 45

Author(s):

Jeremy Hall ◽

Richard J. Wardle ◽

Charles F. Gower ◽

Andrew Kerr ◽

Kevin Coflin ◽

...

Keyword(s):

Canadian Shield ◽

Seismic Survey ◽

Crustal Accretion ◽

Seismic Reflection Data ◽

Reflection Seismic ◽

Reflection Data ◽

New Information ◽

Tectonic Development ◽

Archean Crust ◽

Lower Crustal

As part of the Eastern Canadian Shield Onshore–Offshore Transect (ECSOOT), Lithoprobe acquired 1250 km of deep seismic reflection data along the coast of Labrador and across Ungava Bay, to image evidence of Proterozoic crustal accretion to the Archean nuclei of the Nain and Superior provinces of the Canadian Shield. The relatively pristine Archean crust of the Nain Province has low reflectivity and generally lacks systematic reflector orientations. Reworking of Archean crust on the margins of the Makkovik Province has little effect on this weak signature. In contrast, the Archean crust in the Eastern Churchill (Rae) Province appears to have been overprinted by a strongly developed, whole-crustal, easterly dipping reflection fabric, interpreted to result from Proterozoic collision of the Nain and Superior provinces in the paired New Quebec and Torngat orogens. Juvenile Proterozoic crust in the Makkovik and Grenville provinces also shows strong whole-crustal dipping reflection fabrics, interpretable as outwardly verging structures associated with collisional mobile belts. Crustal thickness varies from 35 to 45 km in Proterozoic provinces, except where thinner in areas probably affected by Mesozoic extension associated with rifting of the Labrador Sea. Dipping reflectors in the mantle are commonly associated with strong lower-crustal dipping reflections in a manner similar to that observed in some modern orogens. The ECSOOT data show that Proterozoic crust in this area has structural forms comparable with those of modern orogens and, inferentially, its tectonic development was controlled by very similar collisional processes.

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Deep marine multichannel seismic reflection data from the Grand Banks, eastern Canadian Continental Margin

10.4095/130422 ◽

1988 ◽

Author(s):

W A Kay ◽

C E Keen

Keyword(s):

Continental Margin ◽

Seismic Reflection ◽

Seismic Reflection Data ◽

Grand Banks ◽

Reflection Data ◽

Multichannel Seismic Reflection ◽

Multichannel Seismic Reflection Data

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SUBMARINE LANDSLIDE AND LOCALIZED TSUNAMI POTENTIALITY OF MENTAWAI BASIN, SUMATRA, INDONESIA

BULLETIN OF THE MARINE GEOLOGY ◽

10.32693/bomg.23.1.2008.5 ◽

2016 ◽

Vol 23 (1) ◽

pp. 1

Author(s):

Haryadi Permana ◽

C. Singh

Keyword(s):

Active Faults ◽

Submarine Landslide ◽

Great Earthquake ◽

Seismic Reflection Data ◽

Seafloor Morphology ◽

Swath Bathymetry ◽

Reflection Data ◽

Different Depths ◽

Landslide Tsunami ◽

Mentawai Island

The new bathymetry and seismic data were acquired during the PreTI-Gap marine survey (February 15 to March 6, 2008). The survey was carried out along the NE margin of Mentawai Island using multi-beam swath bathymetry equipment, and 28-channels seismic streamer and four-airgun source. The first target was the Mega Island region near the epicenter of the 2007 great earthquake. The shallow bathymetry is characterized as a flat coral platform suggesting that 200 km elongated plateau is slowly subsiding without any active faults. Further north, from South Pagai to North of Siberut Islands, the seafloor morphology changes significantly. The deep and wide canyons or valleys produce very rough seafloor morphology between 50 and 1100 m water. In general, the submarine topography shows two break slopes at different depths. Between slope breaks, the undulating, hilly and circular features dominate, possibly caused by landslides. A push-up ridge is observed that dams the sediments eroded within a steep slope northeastward side. The seismic reflection data acquired along 14 dip seismic lines at the NE flank of Mentawai Islands, from Siberut to the South of Pagai Islands. We observed a set of southwestward dipping back thrust bounding the NE margin of the Mentawai Island. Keywords: submarine landslide, tsunami, Mentawai basin, Sumatra. Data batimetri dan seismik baru telah dihasilkan selama survey kelautan PreTi-Gap (15 Februari hingga 6 Maret 2008). Survei dilaksanakan sepanjang tepian timurlaut P. Mentawai menggunakan peralatan multibeam, seismic saluran ganda 28 kanal dengan sumber energi airgun. Sasaran pertama adalah memetakan kawasan pulau dekat pusat gempa tahun 2007. Kenampakan batimetri dangkal dicirikan dengan adanya dataran terumbu karang yang secara perlahan mengalami penurunan tanpa aktifitas sesar. Lebih jauh ke Utar, dari Pagai Selatan ke utara P. Siberut, morfologi dasar laut memperlihatkan perubahan secara signifikan, dimana lembah dasar laut memiliki lebar dan beda kedalaman antara 50 hingga 1100 meter. Secara umum, topografi dasar laut memperlihatkan dua kemiringan pada kedalaman yang berbeda dengan dicirikan adanya kenampakan perlipatan, perbukitan dan bentuk yang melingkar diperkirakan sebagai hasil gelinciran. Sebanyak 14 line data seismik refleksi pada sayap bagian timurlaut P. Mentawai, dari Siberut hingga ke selatan P. Pagai memperlihatkan adanya bukti sesar naik yang miring ke arah baratdaya yang masih satu set dengan tepian timurlaut P. Mentawai. Kata kunci: longsoran bawah laut, tsunami, Cekungan Mentawai, Sumatra.

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