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  • Elsevier  (3)
  • 2015-2019
  • 2010-2014  (3)
  • 2013  (3)
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  • Elsevier  (3)
Years
  • 2015-2019
  • 2010-2014  (3)
Year
  • 1
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    Subduction system variability across the segment boundary of the 2004/2005 Sumatra megathrust earthquakes (2013)
    Elsevier
    In:  Earth and Planetary Science Letters, 365 . pp. 108-119.
    Details
    Publication Date: 2019-09-23
    Description: Subduction zone earthquakes are known to create segmented patches of co-seismic rupture along-strike of a margin. Offshore Sumatra, repeated rupture occurred within segments bounded by permanent barriers, whose origin however is still not fully understood. In this study we image the structural variations across the rupture segment boundary between the Mw 9.1 December 26, 2004 and the Mw 8.6 March 28, 2005 Sumatra earthquakes. A set of collocated reflection and wide-angle seismic profiles are available on both sides of the segment boundary, located offshore Simeulue Island. We present the results of the seismic tomography modeling of wide-angle ocean bottom data, enhanced with MCS data and gravity modeling for the southern 2005 segment of the margin and compare it to the published model for the 2004 northern segment. Our study reveals principal differences in the structure of the subduction system north and south of the segment boundary, attributed to the subduction of 96°E fracture zone. The key differences include a change in the crustal thickness of the oceanic plate, a decrease in the amount of sediment in the trench as well as variations in the morphology and volume of the accretionary prism. These differences suggest that the 96°E fracture zone acts as an efficient barrier in the trench parallel sediment transport, as well as a divider between oceanic crustal blocks of different structure. The variability of seismic behavior is caused by the distinct changes in the morphology of the subduction complex across the boundary related to the difference in the sediment supply.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.epsl.2012.12.032
    Location Call Number Limitation Availability
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 2
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    Seismic Activity offshore Martinique and Dominica islands (Central Lesser Antilles subduction zone) from temporary onshore and offshore seismic networks (2013)
    Elsevier
    In:  Tectonophysics, 603 . pp. 68-78.
    Details
    Publication Date: 2018-01-05
    Description: This work focuses on the analysis of a unique set of seismological data recorded by two temporary networks of seismometers deployed onshore and offshore in the Central Lesser Antilles Island Arc from Martinique to Guadeloupe islands. During the whole recording period, extending from January to the end of August 2007, more than 1300 local seismic events were detected in this area. A subset of 769 earthquakes was located precisely by using HypoEllipse. We also computed focal mechanisms using P-wave polarities of the best azimuthally constrained earthquakes. We detected earthquakes beneath the Caribbean forearc and in the Atlantic oceanic plate as well. At depth seismicity delineates the Wadati–Benioff Zone down to 170 km depth. The main seismic activity is concentrated in the lower crust and in the mantle wedge, close to the island arc beneath an inner forearc domain in comparison to an outer forearc domain where little seismicity is observed. We propose that the difference of the seismicity beneath the inner and the outer forearc is related to a difference of crustal structure between the inner forearc interpreted as a dense, thick and rigid crustal block and the lighter and more flexible outer forearc. Seismicity is enhanced beneath the inner forearc because it likely increases the vertical stress applied to the subducting plate.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    DOI: 10.1016/j.tecto.2011.08.006
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
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    Structure of the Lesser Antilles subduction forearc and backstop from 3D seismic refraction tomography (2013)
    Elsevier
    In:  Tectonophysics, 603 . pp. 55-67.
    Details
    Publication Date: 2017-12-05
    Description: In 2007 the Sismantilles II experiment was conducted to constrain structure and seismicity in the central Lesser Antilles subduction zone. The seismic refraction data recorded by a network of 27 OBSs over an area of 65 km×95 km provide new insights on the crustal structure of the forearc offshore Martinique and Dominica islands. The tomographic inversion of first arrival travel times provides a 3D P-wave velocity model down to 15 km. Basement velocity gradients depict that the forearc is made up of two distinct units: A high velocity gradient domain named the inner forearc in comparison to a lower velocity gradient domain located further trenchward named the outer forearc. Whereas the inner forearc appears as a rigid block uplifted and possibly tilted as a whole to the south, short wavelength deformations of the outer forearc basement are observed, beneath a 3 to 6 km thick sedimentary pile, in relation with the subduction of the Tiburon Ridge and associated seafloor reliefs. North, offshore Dominica Island, the outer forearc is 70 km wide. It extends as far as 180 km to the east of the volcanic front where it acts as a backstop on which the accretionary wedge developed. Its width decreases strongly to the south to terminate offshore Martinique where the inner forearc acts as the backstop. The inner forearc is likely the extension at depth of theMesozoicmagmatic crust outcropping to the north in La Désirade Island and along the scarp of the Karukera Spur. The outer forearc could be either the eastern prolongation of the inner forearc, but the crust was thinned and fractured during the past tectonic history of the area or by recent subduction processes, or an oceanic terrane more recently accreted to the island arc.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    DOI: 10.1016/j.tecto.2011.09.021
    Location Call Number Limitation Availability
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    OceanRep: Article in a Scientific Journal - peer-reviewed
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