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| Schimmel, M.; Stutzmann, E.; Ardhuin, Fabrice; Gallart, J.. |
| We quantify, analyze, and characterize the frequency-dependent microseismic noise recorded by worldwide distributed seismic stations. Microseismic noise is generated through the interaction of ocean waves. It is the strongest ambient noise, and it is observed everywhere on Earth. We introduce a new approach which permits us to detect polarized signals in the time-frequency domain and which we use to characterize the microseismic noise. We analyze 7 years of continuous seismograms from the global GEOSCOPE network. Microseisms are dominated by Rayleigh waves, and we therefore focus on elliptically polarized signals. The polarized signals are detected in the time-frequency domain through a degree of polarization measure. We design polarization spectra and... |
| Tipo: Text |
Palavras-chave: Microseismic noise; Polarization; Primary and secondary microseisms; Seismology. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00041/15219/12713.pdf |
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| Person, Roland; Aoustin, Yannick; Blandin, Jerome; Marvaldi, Jean; Rolin, Jean-francois. |
| For a long time, deep-sea investigation relied on autonomous bottom landers. Landers call vary in size from 200 kg weight to more than 2 t for the heaviest scientific landers and are used during exploration cruises oil medium periods, from one week to some months. Today, new requirements appear. Scientists want to understand in detail the phenomena outlined during exploration cruises, to elaborate a model for future forecasting. For this, it is necessary to deploy instrumentation at a precise location often for a long period. A new mode of ocean science investigation Using long-term seafloor observatories to obtain four dimensional data sets has appeared. Although this concept has been proposed for many years, the high level of investment required limits... |
| Tipo: Text |
Palavras-chave: Environment; Seismology; Global change; Multidisciplinary long term observatories; Landers. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-3604.pdf |
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| Avedik, Felix. |
| Detecting and localizing nuclear blasts was an essential stimulus of the actions undertaken in the 1960's to emplace seismological observatories on the seafloor. The plate-tectonic theory, in which the oceanic areas play a major role, greatly accelerated the evolution of modern oceanology. The contribution of Ifremer's department of Marine Geosciences, in helping to advance this area of research, has been significant since 1972. The need for refraction studies to explore the deep structure of the margins and ocean-continent transition zones led us to design a deep-sea Ocean Bottom Seismograph (OBS) MK I in 1975, rated to 6,000 metres depth. This system introduced, for the first time, the concept of "isolated seismic sensors". This principle was adopted... |
| Tipo: Text |
Palavras-chave: Geology; Seismometers; Digital records; Seismology; Surveys; Marine technology; Seismic data. |
| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/1990/acte-1140.pdf |
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| Hetenyi, Gyorgy; Molinari, Irene; Clinton, John; Bokelmann, Gotz; Bondar, Istvan; Crawford, Wayne C.; Dessa, Jean-xavier; Doubre, Cecile; Friederich, Wolfgang; Fuchs, Florian; Giardini, Domenico; Graczer, Zoltan; Handy, Mark R.; Herak, Marijan; Jia, Yan; Kissling, Edi; Kopp, Heidrun; Korn, Michael; Margheriti, Lucia; Meier, Thomas; Mucciarelli, Marco; Paul, Anne; Pesaresi, Damiano; Piromallo, Claudia; Plenefisch, Thomas; Plomerova, Jaroslava; Ritter, Joachim; Rumpker, Georg; Sipka, Vesna; Spallarossa, Daniele; Thomas, Christine; Tilmann, Frederik; Wassermann, Joachim; Weber, Michael; Weber, Zoltan; Wesztergom, Viktor; Zivcic, Mladen; Abreu, Rafael; Allegretti, Ivo; Apoloner, Maria-theresia; Aubert, Coralie; Besancon, Simon; De Berc, Maxime Bes; Brunel, Didier; Capello, Marco; Carman, Martina; Cavaliere, Adriano; Cheze, Jerome; Chiarabba, Claudio; Cougoulat, Glenn; Cristiano, Luigia; Czifra, Tibor; D'Alema, Ezio; Danesi, Stefania; Daniel, Romuald; Dannowski, Anke; Dasovic, Iva; Deschamps, Anne; Egdorf, Sven; Fiket, Tomislav; Fischer, Kasper; Funke, Sigward; Govoni, Aladino; Groschl, Gidera; Heimers, Stefan; Heit, Ben; Herak, Davorka; Huber, Johann; Jaric, Dejan; Jedlicka, Petr; Jund, Helene; Klingen, Stefan; Klotz, Bernhard; Kolinsky, Petr; Kotek, Josef; Kuhne, Lothar; Kuk, Kreso; Lange, Dietrich; Loos, Jurgen; Lovati, Sara; Malengros, Deny; Maron, Christophe; Martin, Xavier; Massa, Marco; Mazzarini, Francesco; Metral, Laurent; Moretti, Milena; Munzarova, Helena; Nardi, Anna; Pahor, Jurij; Pequegnat, Catherine; Petersen, Florian; Piccinini, Davide; Pondrelli, Silvia; Prevolnik, Snjezan; Racine, Roman; Regnier, Marc; Reiss, Miriam; Salimbeni, Simone; Santulin, Marco; Scherer, Werner; Schippkus, Sven; Schulte-kortnack, Detlef; Solarino, Stefano; Spieker, Kathrin; Stipcevic, Josip; Strollo, Angelo; Sule, Balint; Szanyi, Gyongyver; Szucs, Eszter; Thorwart, Martin; Ueding, Stefan; Vallocchia, Massimiliano; Vecsey, Ludek; Voigt, Rene; Weidle, Christian; Weyland, Gauthier; Wiemer, Stefan; Wolf, Felix; Wolyniec, David; Zieke, Thomas. |
| The AlpArray programme is a multinational, European consortium to advance our understanding of orogenesis and its relationship to mantle dynamics, plate reorganizations, surface processes and seismic hazard in the Alps-Apennines-Carpathians-Dinarides orogenic system. The AlpArray Seismic Network has been deployed with contributions from 36 institutions from 11 countries to map physical properties of the lithosphere and asthenosphere in 3D and thus to obtain new, high-resolution geophysical images of structures from the surface down to the base of the mantle transition zone. With over 600 broadband stations operated for 2 years, this seismic experiment is one of the largest simultaneously operated seismological networks in the academic domain, employing... |
| Tipo: Text |
Palavras-chave: Seismology; Alps; Seismic network; Geodynamics; Seismic imaging; Mountain building. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00690/80173/83243.pdf |
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| Plasman, Matthieu; Hautot, Sophie; Tarits, Pascal; Gautier, Stephanie; Tiberi, Christel; Le Gall, Bernard; Mtelela, Khalfan; Gama, Remigius. |
| Continental break-up is controlled by several parameters and processes (rheology, inherited structures, magmatism, etc). Their impact, chronology and interactions are still poorly known and debated, particularly when rifting interacts with cratons. In order to better understand the rifting initiation in a cratonic lithosphere, we analysed 22 magnetotelluric (MT) soundings collected along two East-West profiles in two different rift segments of the North Tanzanian Divergence. The North Tanzanian Divergence, where the East African Rift is at its earliest stage, is a remarkable example of the transition between magmatic to amagmatic rifting with two clearly identified segments. Only separated by a hundred kilometers, these segments, Natron (North) and Manyara... |
| Tipo: Text |
Palavras-chave: Magnetotellurics; 3-D inversion; North Tanzanian Divergence; East African rift; Lithospheric structure; CO2 content; Seismology; Joint interpretation. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00637/74897/76062.pdf |
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| Vandemeulebrouck, J.; Roux, Philippe; Cros, Estelle. |
| Old Faithful Geyser in Yellowstone National Park (USA) has attracted numerous scientific investigations for over two centuries to better understand its geological structure, the physics of its eruptions, and the controls of its intermittency. Using data acquired with a seismic array in 1992, we track the sources of hydrothermal tremor produced by boiling and cavitation inside the geyser. The location of seismic sources identifies a previously unknown lateral cavity at 15m below the surface, on the SW side of the vent, and connected to the conduit. This reservoir is activated at the beginning of each geyser eruption cycle and plays a major role in the oscillatory behavior of the water level in the conduit before each eruption. |
| Tipo: Text |
Palavras-chave: Geyser; Hydrothermal; Seismology; Old Faithful; Tremor. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00171/28263/26703.pdf |
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