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Published on May 04, 2016

Le séisme de magnitude 7.8 survenu le 16 avril 2016 en Equateur est un séisme de subduction interface. La plaque océanique Nazca plonge sous la plaque Amérique du Sud à une vitesse moyenne de 5 cm/an. Les cartes de couplage établies avant le séisme de 2016 (Chlieh et al. 2014 ; Nocquet et al. 2014) montrent qu’il se situe au niveau d’une zone fortement couplée de l’interface sismogène entre les deux plaques. Le séisme s’est produit à l’intérieur de la grande zone de rupture du séisme de 1906 (…)

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Published on April 22, 2016

The earthquake sequence started by a M6.2 earthquake at 12:26 UTC(21:26 JST) on 14th April. The shaking was intense for its size with a maximum acceleration of up to 1560 gals. Ground deformation by InSAR indicates that the earthquake rupture did not break the surface, making the shaking even stronger.
The aftershock activity was high right after the M6.2 earthquake with a few earthquakes of magnitude of almost 6. b-value of aftershocks during hours after the M6.2 earthquake was about 0.7, (…)

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Published on April 21, 2016

First detected fifteen years ago, slow slip events have now been observed in many parts of the world, opening up a new window into the processes at work in seismic faults. With magnitudes of up to 7.5 on the Richter scale, these earthquakes, which last from several weeks to several months, could eventually help improve mapping of seismic risk.

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Published on April 20, 2016

Des outils de modélisation et d’imagerie sismique ont été développés dans le cadre d’une collaboration interdisciplinaire regroupant des géophysiciens, des mathématiciens et des informaticiens de Géoazur à Sophia Antipolis, d’ISTerre et du LJK de Grenoble, dans le cadre du projet SEISCOPE et de l’Université de Toulouse (IRIT) et du LIP de Lyon dans le cadre du projet MUMPS pour effectuer un cas d’étude visant à imager en 3D un réservoir pétrolier norvégien localisé en mer du Nord. Les moyens (…)

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Published on April 11, 2016

Scientists have found a large deposit of horse manure in the Col de Traversette pass (2947m. high), near the French-Italian border, that might be a remains of Hannibal’s invasion.
Indeed, in 218 BC, the Carthaginian general led an army of 30,000 soldiers, 15,000 horses and mules and 37 war elephants across the Alps into Italy, a bold move that led to one of the greatest victories of the Second Punic War with Rome. This hard crossing is memorable but historians are still divised on the (…)

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Published on April 04, 2016

Earth scientists from the Institut des Sciences de la Terre de Grenoble, the Vernadsky Institute (Moscow), Centre de Recherches Pétrographiques et Géochimiques de Nancy (CNRS, Université de Lorraine), in collaboration with German (GEOMAR, Kiel) researchers, have studied komatiites (unusual volcanic rocks) from the 2.7 billion year old Abitibi Belt in Canada (Fig.1). They obtained the first analyses of the concentrations of water and mobile elements (Rb, Ba, Cl, Pb, Sr etc) in small (tens of (…)

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Published on March 30, 2016

University Grenoble Alpes is the best French university and on top 50 in the world in in the domain "Earth and marine sciences" by QS World University Rankings 2016.
The britannic company Quacquarelli Symonds (QS), specialized in information for students and yound professionals, published on 22 March 2016 on its website (Top Universities) its rankings per discipline: 42 rankings gathering 5 domains (Arts & Humanities, Engineering & Technology, Life sciences & Medicine, Natural (…)

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Published on March 29, 2016

The Himalaya is the largest and one of the most active mountain belts on Earth. Active tectonic processes (dramatically underlined by the 2015 Gorkha earthquake) and a vigorous monsoon climate together lead to very strong, and often catastrophic, erosion processes. Whether tectonics or climate is most important in controlling the topography and erosion of the Himalaya has been strongly debated.
A possible answer to this question could come from studying lateral (east-west) variations in (…)

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Published on March 23, 2016

March 15th has occurred a multidisciplinary day to pay tribute to Denys Schmitt and discuss about the scientific thematics he developped in Institut Néel and then in ISTerre: solid state physics; geophysics; quadrupole effects in intermetallic rare earth; magnetism at different levels; precession and nutations: when the poles are playing tricks on us; modes in the Earth’s core; dynamo experiments; d’Alfvén waves... This event, co-organized by ISTerre and the laboratory Louis Néel, has been a (…)

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Published on March 03, 2016

Afin de retracer à terme la composition chimique des paléo-océans, une équipe de chercheurs d’ISTerre, du Laboratoire de géologie de Lyon - Terre, planète, environnement (LGL-TPE) et du European Synchrotron Radiation Facility (ESRF) a cartographié la composition en éléments traces de coccolithes fossiles pour connaître leur composition chimique.
Les coccolithes sont de petites (5-10 µm) pièces calcaires composant le squelette (coccosphère) d’algues marines unicellulaires et (…)

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