| Registro completo |
| Provedor de dados: |
ArchiMer
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| País: |
France
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| Título: |
The GROSMarin experiment: three dimensional crustal structure of the North Ligurian margin from refraction tomography and preliminary analysis of microseismic measurements
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| Autores: |
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
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| Data: |
2011
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| Ano: |
2011
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| Palavras-chave: |
North Ligurian margin
Ocean bottom seismometers
Refraction tomography
Velocity structure
Crustal units
Microseismicity
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| Resumo: |
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 tomography. We present here a preliminary analysis of the seismicity recorded during this experiment and a tomographic model of the margin structures obtained using data from the offshore network only. Our results support the existence of a high velocity zone at the base of a domain interpreted as transitional between continental and oceanic ones, on the northern part of the deep basin. A very similar pattern is observed across the neighbouring margin of the Gulf of Lions and is most likely related to serpentinisation of the underlying mantle during late rifting and continental break-up. North of this transition zone, we observe the basinward crustal thinning of the continental crust beneath the margin that seemingly narrows eastward. To the south, our results hint at transition to the oceanic domain. In contrast, our velocity distribution does not reveal a transition along strike between transitional and oceanic domains, as previous works suggest. Some microseismic activity was recorded throughout the duration of the experiment, on land and at sea. The number of detected events and precision of location were both improved by our considering French and Italian permanent networks. The detection capabilities of our dense network still need to be fully exploited.
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| Tipo: |
Text
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| Idioma: |
Inglês
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| Identificador: |
http://archimer.ifremer.fr/doc/00214/32544/31020.pdf
DOI:10.2113/gssgfbull.182.4.305
http://archimer.ifremer.fr/doc/00214/32544/
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| Editor: |
Soc Geol France
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| Formato: |
application/pdf
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| Fonte: |
Bulletin De La Societe Geologique De France (0037-9409) (Soc Geol France), 2011 , Vol. 182 , N. 4 , P. 305-321
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| Direitos: |
2011 by the Societe Geologique de France
info:eu-repo/semantics/openAccess
restricted use
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