Manioc : Portail | resultats 101 - 120 pour la recherche: éruption

A deluge of boulders, Basse-Pointe May 30,1902
Auteur(s) : Heilprin, Angelo (1853-1907)

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Fragment of manuscript from the debris of Saint-Pierre. Mention of Pompeii in the first line of the upper figure
Auteur(s) : Heilprin, Angelo (1853-1907)

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Physical and remineralization processes govern the cobalt distribution in the deep western Atlantic Ocean
Auteur(s) : Dulaquais, Gabriel Boye, Marie Rijkenberg, M. J. A. Carton, Xavier

Éditeur(s) : Copernicus Gesellschaft Mbh
Résumé : The distributions of the bio-essential trace element dissolved cobalt (DCo) and the apparent particulate Co (PCo) are presented along the GEOTRACES-A02 deep section from 64(o) N to 50(o) S in the western Atlantic Ocean (longest section of international GEOTRACES marine environment program). PCo was determined as the difference between total cobalt (TCo, unfiltered samples) and DCo. DCo concentrations ranged from 14.7 pM to 94.3 pM, and PCo concentrations from undetectable values to 18.8 pM. The lowest DCo concentrations were observed in the subtropical domains, and the highest in the low-oxygenated Atlantic Central Waters (ACW), which appears to be the major reservoir of DCo in the western Atlantic. In the Antarctic Bottom Waters, the enrichment in DCo with aging of the water mass can be related to suspension and redissolution of bottom sediments a well as diffusion of DCo from abyssal sediments. Mixing and dilution of deep water masses, rather than scavenging of DCo onto settling particles, generated the meridional decrease of DCo along the southward large-scale circulation in the deep western Atlantic. Furthermore, the apparent scavenged profile of DCo observed in the deep waters likely resulted from the persistence of relatively high concentrations in intermediate waters and low DCo concentrations in underlaying bottom waters. We suggest that the 2010 Icelandic volcanic eruption could have been a source of DCo that could have been transported into the core of the Northeast Atlantic Deep Waters. At intermediate depths, the high concentrations of DCo recorded in the ACW linearly correlated with the apparent utilization of oxygen (AOU), indicating that remineralization of DCo could be significant (representing up to 37% of the DCo present). Furthermore, the preferential remineralization of phosphate (P) compared to Co in these low-oxygenated waters suggests a decoupling between the deep cycles of P and Co. The vertical diffusion of DCo from the ACW appears to be a significant source of DCo into the surface waters of the equatorial domain. Summarizing, the dilution due to mixing processes rather than scavenging of DCo and the above-mentioned remineralization could be the two major pathways controlling the cycling of DCo into the intermediate and deep western Atlantic.
Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2014 , Vol. 11 , N. 6 , P. 1561-1580

Droits : Author(s) 2014. CC Attribution 3.0 License.
http://archimer.ifremer.fr/doc/00241/35223/33727.pdf
DOI:10.5194/bg-11-1561-2014
http://archimer.ifremer.fr/doc/00241/35223/

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The tower of Pelée with its supporting dome, view looking north-northwest. Photograph taken at the crater-rim June 13, 1903
Auteur(s) : Heilprin, Angelo (1853-1907)

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Ash-cloud of Pelée, view taken from Assier
Auteur(s) : Heilprin, Angelo (1853-1907)

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« Bombe volcanique » projetée par le Mont-Pelée. 16 février 1930
Auteur(s) : Hersilie-Héloïse
Année de publication :

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13 avril 1930. Bombe volcanique de 1902, sur la rive droite de la rivière Sècle, à 2 km. Environ de la côte ( Près de l'habitation Isnard )
Auteur(s) : Veille, I.
Année de publication :

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Ce qui reste du Morne Lacroix, après l'éruption de 1902. Excursion du 25 août 1929
Auteur(s) : Sully fils
Année de publication :

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Steam-ash clouds in the afternoon of August 30, 1902, strongly illumined clouds with rapidly unfolding whorls
Auteur(s) : Heilprin, Angelo (1853-1907)

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Une éruption de la Montagne Pelée. Vue prise à Saint-Pierre le 24 Novembre 1929
Auteur(s) : Veille, I.
Année de publication :

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Le commandant du Suchet, M. Le Bris et son état major
Auteur(s) : Hess, Jean (1862-1926)

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DEM-based model for reconstructing volcano's morphology from primary volcanic landforms
Auteur(s) : Gayer, Eric Lopez, Philippe Michon, Laurent
Auteurs secondaires : Institut de Physique du Globe de Paris (IPGP) ; Institut national des sciences de l'Univers (INSU - CNRS) - IPG PARIS - Université Paris Diderot - Paris 7 (UPD7) - Université de la Réunion (UR) - Centre National de la Recherche Scientifique (CNRS) Evolution Paris Seine ; Université des Antilles et de la Guyane (UAG) - Université Pierre et Marie Curie - Paris 6 (UPMC) - Université Nice Sophia Antipolis (UNS) ; Université Côte d'Azur (UCA) - Université Côte d'Azur (UCA) - Centre National de la Recherche Scientifique (CNRS) Laboratoire GéoSciences Réunion (LGSR) ; Université de la Réunion (UR) - Institut de Physique du Globe de Paris

Éditeur(s) : HAL CCSD
Résumé : International audience
Volumes of magma intruded in and emitted by volcanoes through time can be estimated by reconstruction of vol-cano's morphology and time sequence. Classical approaches for quantifying magma volumes on active volcanoes are based on the difference between pre-and post-eruption digital elevation models (DEM), but this kind of approach needs the pre-eruptive surfaces to be available. For old and eroded volcanoes these surfaces are poorly constrained. However, because the geometrical form of many volcanic edifices exhibits a remarkable symmetry we propose, here, a new approach using primary volcanic landforms in order to estimate the amount of the both erupted and eroded material and to locate eruptive centers. A large fraction of composite volcanoes have near constant slope on their flanks and a form that is concave upwards near their summits. But many phenomena can lead to non-symetrical edifices and complex morphologies can result, for example from parasitic centers of volcanism on the flanks, from alternation of short effusive and explosive construction phases, from flank or caldera collapses, or from glacial and other types of erosion. In this study we propose that, on the first order approximation, complex morphologies can be modeled by piling regular cones. In this model, cones centers and slopes are derived by fitting primary volcanic landform with a linear function :elevation=f(distance from center). Such an approach allows to estimate both errors on location of the eruptive center and on the volume of the resulting cones. This model can then be used for quantifying volume of erupted and eroded material, and for quantifying catastrophic events as giant landslides or flank collapse. This approach is tested on four different active volcanoes : Mount Mayon (Philippines), Mount Fuji (Japan), Mount Etna (Sicily) and Mount Teide (Canary Island) to estimate errors in volume between modeled and actual edifices. It is then used on volcanoes of La Réunion hotspot to reconstruct the Piton des Neiges and Piton de la Fournaise volcanoes at its different stages of growing.
EGU 2014
Vienna, Austria

hal-01386609
http://hal.univ-reunion.fr/hal-01386609

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