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  • 1
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    BedMachine v3: Complete Bed Topography and Ocean Bathymetry Mapping of Greenland From Multibeam Echo Sounding Combined With Mass Conservation (2017)
    AGU (American Geophysical Union) | Wiley
    In:  Geophysical Research Letters, 44 (21). 11.051-11.061.
    Details
    Publication Date: 2020-02-06
    Description: Greenland's bed topography is a primary control on ice flow, grounding line migration, calving dynamics, and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic water (AW) that rapidly melts and undercuts Greenland's marine-terminating glaciers. Here we present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness data through a mass conservation approach. A new 150 m horizontal resolution bed topography/bathymetric map of Greenland is constructed with seamless transitions at the ice/ocean interface, yielding major improvements over previous data sets, particularly in the marine-terminating sectors of northwest and southeast Greenland. Our map reveals that the total sea level potential of the Greenland ice sheet is 7.42 ± 0.05 m, which is 7 cm greater than previous estimates. Furthermore, it explains recent calving front response of numerous outlet glaciers and reveals new pathways by which AW can access glaciers with marine-based basins, thereby highlighting sectors of Greenland that are most vulnerable to future oceanic forcing.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1002/2017GL074954
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 2
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    Submarine mass wasting and associated tsunami risk offshore western Thailand, Andaman Sea, Indian Ocean (2012)
    Copernicus Publications (EGU)
    In:  Natural Hazards and Earth System Sciences, 12 (8). pp. 2609-2630.
    Details
    Publication Date: 2019-05-23
    Description: 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.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.5194/nhess-12-2609-2012
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
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    Seismic rupture during the 1960 Great Chile and the 2010 Maule earthquakes limited by a giant Pleistocene submarine slope failure (2013)
    Wiley
    In:  Terra Nova, 25 . pp. 472-477.
    Details
    Publication Date: 2019-09-23
    Description: Determining factors that limit coseismic rupture is important to evaluate the hazard of powerful subduction zone earthquakes such as the 2011 Tohoku-Oki event (Mw = 9.0). In 1960 (Mw = 9.5) and 2010 (Mw = 8.8), Chile was hit by such powerful earthquakes, the boundary of which was the site of a giant submarine slope failure with chaotic debris subducted to seismogenic zone depth. Here, a continuous décollement is absent, whereas away from the slope failure, a continuous décollement is seismically imaged. We infer that underthrusting of inhomogeneous slide deposits prevents the development of a décollement, and thus the formation of a thin continuous slip zone necessary for earthquake rupture propagation. Thus, coseismic rupture during the 1960 and 2010 earthquakes seems to be limited by underthrusted upper plate mass-wasting deposits. More generally, our results suggest that upper plate dynamics and resulting surface processes can play a key role for determining rupture size of subduction zone earthquakes
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1111/ter.12060
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
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    Bathymetry data reveal glaciers vulnerable to ice-ocean interaction in Uummannaq and Vaigat glacial fjords, west Greenland (2016)
    AGU (American Geophysical Union) | Wiley
    In:  Geophysical Research Letters, 43 (6). pp. 2667-2674.
    Details
    Publication Date: 2019-02-01
    Description: Marine-terminating glaciers play a critical role in controlling Greenland's ice sheet mass balance. Their frontal margins interact vigorously with the ocean, but our understanding of this interaction is limited, in part, by a lack of bathymetry data. Here we present a multibeam echo sounding survey of 14 glacial fjords in the Uummannaq and Vaigat fjords, west Greenland, which extends from the continental shelf to the glacier fronts. The data reveal valleys with shallow sills, overdeepenings (〉 1300 m) from glacial erosion, and seafloor depths 100-1000 m deeper than in existing charts. Where fjords are deep enough, we detect the pervasive presence of warm, salty Atlantic Water (AW) (〉 2.5 degrees C) with high melt potential, but we also find numerous glaciers grounded on shallow (〈 200 m) sills, standing in cold (〈 1 degrees C) waters in otherwise deep fjords, i.e., with reduced melt potential. Bathymetric observations extending to the glacier fronts are critical to understand the glacier evolution.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1002/2016GL067832
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 5
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    Bathymetry of Southeast Greenland From Oceans Melting Greenland (OMG) Data (2019)
    AGU (American Geophysical Union) | Wiley
    In:  Geophysical Research Letters, 46 (20). pp. 11197-11205.
    Details
    Publication Date: 2022-01-31
    Description: Southeast Greenland has been a major participant in the ice sheet mass loss over the last several decades. Interpreting the evolution of glacier fronts requires information about their depth below sea level and ocean thermal forcing, which are incompletely known in the region. Here, we combine airborne gravity and multibeam echo sounding data from the National Aeronautics and Space Administration's Oceans Melting Greenland (OMG) mission with ocean probe and fishing boat depth data to reconstruct the bathymetry extending from the glacier margins to the edges of the continental shelf. We perform a three‐dimensional inversion of the gravity data over water and merge the solution with a mass conservation reconstruction of bed topography over land. In contrast with other parts of Greenland, we find few deep troughs connecting the glaciers to the sources of warm Atlantic Water, amidst a relatively uniform, shallow (350 m) continental shelf. The deep channels include the Kangerlugssuaq, Sermilik, Gyldenløve, and Tingmiarmiut Troughs.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1029/2019GL083953
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 6
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    Retreat of Humboldt Gletscher, North Greenland, Driven by Undercutting From a Warmer Ocean (2021)
    AGU (American Geophysical Union) | Wiley
    Details
    Publication Date: 2024-02-07
    Description: Humboldt Gletscher is a 100‐km wide, slow‐moving glacier in north Greenland which holds a 19‐cm global sea level equivalent. Humboldt has been the fourth largest contributor to sea level rise since 1972 but the cause of its mass loss has not been elucidated. Multi‐beam echo sounding data collected in 2019 indicate a seabed 200 m deeper than previously known. Conductivity temperature depth data reveal the presence of warm water of Atlantic origin at 0°C at the glacier front and a warming of the ocean waters by 0.9 ± 0.1°C since 1962. Using an ocean model, we reconstruct grounded ice undercutting by the ocean, combine it with calculated retreat caused by ice thinning to floatation, and are able to fully explain the observed retreat. Two thirds of the retreat are caused by undercutting of grounded ice, which is a physical process not included in most ice sheet models.
    Type: Article , PeerReviewed
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
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