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| Klingelhoefer, Frauke; Gutscher, M. -a.; Ladage, S.; Dessa, J. -x.; Graindorge, D.; Franke, D.; Andre, Camille; Permana, H.; Yudistira, T.; Chauhan, A.. |
| The 26 December 2004 Sumatra earthquake (M-w = 9.1) initiated around 30 km depth and ruptured 1300 km of the Indo-Australian-Sunda plate boundary. During the Sumatra-OBS (ocean bottom seismometer) survey, a wide-angle seismic profile was acquired across the epicentral region. A seismic velocity model was obtained from combined travel time tomography and forward modeling. Together with reflection seismic data from the SeaCause II cruise, the deep structure of the source region of the great earthquake is revealed. Four to five kilometers of sediments overlie the oceanic crust at the trench, and the subducting slab can be imaged down to a depth of 35 km. We find a crystalline backstop 120 km from the trench axis, below the fore-arc basin. A high-velocity zone... |
| Tipo: Text |
Palavras-chave: Middle america trench; Fore arc basin; Bottom seismographic observation; Subduction zone; Crustal structure; Accretionary prism; Mantle serpentinization; Aftershock distribution; Megathrust earthquakes; Velocity structure. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00000/11155/7737.pdf |
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| Souza, Aj; Simpson, Jh; Harikrishnan, M; Malarkey, J. |
| The intensity, structure and variability of the slope current have been determined from 16 months of observations with Acoustic Doppler Current Profilers (ADCP) and conventional current meters on a cross-slope section at the Hebridean shelf edge during the Shelf Edge Study (SES) programme. After removal of the tidal signals, the mean flow over the upper slope is found to be closely parallel to the topography with speeds of . 20 cmEs.1. The flow extends down to a depth of 500 m and is predominantly barotropic, especially in winter when the flow is practically uniform between 350 m and the surface. In summer, there is a significant baroclinic component with a pronounced maximum in current at a depth of about 200 m but more than 80% of the kinetic energy is... |
| Tipo: Text |
Palavras-chave: Slope current; Seasonality; Velocity structure. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00292/40275/38648.pdf |
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| Dessa, Jean-xavier; Simon, Soazig; Lelievre, Marjorie; Beslier, Marie-odile; Deschamps, Anne; Bethoux, Nicole; Solarino, Stefano; Sage, Francoise; Eva, Elena; Ferretti, Gabriele; Bellier, Olivier; Eva, Claudio. |
| The deep structure of the North Ligurian margin and its contiguous Ligurian basin as well as the seismicity recorded in these zones are neither well understood nor precisely constrained. In order to better address these questions, there is a need for offshore instrumenting, which was realised for a duration of nearly 6 months during the GROSMarin (Grand Reseau d'Observation Sous-Marin) experiment. An array of 21 ocean bottom seismometers was deployed over the most active area of the margin and was complemented on land by mobile seismological stations that densified existing permanent networks. We also realised the acquisition of deep refraction seismic shots at sea in order to get a 3D distribution of velocities along the margin through travel time... |
| Tipo: Text |
Palavras-chave: North Ligurian margin; Ocean bottom seismometers; Refraction tomography; Velocity structure; Crustal units; Microseismicity. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00214/32544/31020.pdf |
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