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| Ballu, Valerie; Bouin, Marie-noelle; Simeoni, Patricia; Crawford, Wayne C.; Calmant, Stephane; Bore, Jean-michel; Kanas, Tony; Pelletier, Bernard. |
| Since the late 1990s, rising sea levels around the Torres Islands (north Vanuatu, southwest Pacific) have caused strong local and international concern. In 2002-2004, a village was displaced due to increasing sea incursions, and in 2005 a United Nations Environment Programme press release referred to the displaced village as perhaps the world's first climate change "refugees." We show here that vertical motions of the Torres Islands themselves dominate the apparent sea-level rise observed on the islands. From 1997 to 2009, the absolute sea level rose by 150 +/- 20 mm. But GPS data reveal that the islands subsided by 117 +/- 30 mm over the same time period, almost doubling the apparent gradual sea-level rise. Moreover, large earthquakes that occurred just... |
| Tipo: Text |
Palavras-chave: Geodesy; Seismic cycle; Island arcs; Vertical motion. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00144/25575/23734.pdf |
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| Auzende, Jean-marie; Ballu, Valerie; Batiza, R; Bideau, Daniel; Cormier, Mh; Fouquet, Yves; Geistdoerfer, Patrick; Lagabrielle, Yves; Sinton, J; Spadea, P. |
| The submersible-study of four segments of the East Pacific Rise between 17 degrees and 18 degrees 40'S, where the spreading rate is greater than 150 mm/a, allows us to confirm the variability of the accretion processes. The segment between 17 degrees and 17 degrees 30'S shows an intense present-day magmatic activity. The one between 18 degrees 10' and 18 degrees 22'S shows a mainly tectonic activity. The segment between 18 degrees 22' and 18 degrees 37'S is an intermediate stage with an axial graben in which fresh lavas were emplaced by an extremely young eruption. On all the segments the hydrothermal activity exists ranging from shimmering water up to black smokers, It is associated with different stages of animal colonization. |
| Tipo: Text |
Palavras-chave: Océan Pacifique; Dorsale ultra-rapide; Magmatisme; Tectonique; Hydrothermalisme.; PACIFIC OCEAN; ULTRA-FAST SPREADING RIDGE; MAGMATISM; TECTONICS; HYDROTHERMALISM. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00183/29458/27840.pdf |
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| Lange, Dietrich; Kopp, Heidrun; Royer, Jean-yves; Henry, Pierre; Cakir, Ziyadin; Petersen, Florian; Sakic, Pierre; Ballu, Valerie; Bialas, Joerg; Ozeren, Mehmet Sinan; Ergintav, Semih; Geli, Louis. |
| Using offshore geodetic observations, we show that a segment of the North Anatolian Fault in the central Sea of Marmara is locked and therefore accumulating strain. The strain accumulation along this fault segment was previously extrapolated from onshore observations or inferred from the absence of seismicity, but both methods could not distinguish between fully locked or fully creeping fault behavior. A network of acoustic transponders measured crustal deformation with mm-precision on the seafloor for 2.5 years and did not detect any significant fault displacement. Absence of deformation together with sparse seismicity monitored by ocean bottom seismometers indicates complete fault locking to at least 3 km depth and presumably into the crystalline... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00507/61838/65897.pdf |
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| Rawat, Arshad; Ardhuin, Fabrice; Ballu, Valerie; Crawford, Wayne; Corela, Carlos; Aucan, Jerome. |
| Ocean infragravity (IG) waves are low-frequency waves generated along shorelines by incident seas and swell and with heights of the order of 1 cm in the open ocean. Despite these small amplitudes, they can be of much importance for ice shelf break up and errors in measurements of sea level by future satellite altimeters. A combination of numerical model results and in situ data is used to show that bottom pressure signals in the infragravity frequency band can be dominated by bursts of energy that travel across ocean basins, and can last for several days. Two particularly strong events recorded in 2008 are studied, one in the North-Pacific and the other in the North-Atlantic. It is shown that infragravity waves can travel across whole oceans basins with... |
| Tipo: Text |
Palavras-chave: Infragravity waves; DART; Global wave model. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00233/34465/32860.pdf |
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