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Maggi A., Debayle E., Priestley K., Barruol G., Ontaine F. & Remond D. (2003). Surface waveform tomography of the upper mantle under the South Pacific super-swell from analysis of Plume“ broad-band data.”.
Abstract: ESC-EUG-AGU joint Assembly. Nice France
Programme: 906
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Casula, G.; Danesi, S.; Dubbini, M.; Vittuari, L. (2007). Tidal forcing on David Glacier and Drygalski Ice Tongue. The National Academy Press, Washington DC.
Abstract: During the 2005-06 Austral Summer, we carried out a joint observational campaign in the area of the David Glacier, South Victoria Land, with the aim of collecting simultaneous time series of geodetic and seismological data. We installed 7 temporary seismographic stations on rock outcrops surrounding the glacier and 3 temporary geodetic stations both on flowing ice and on rock. The seismic network registered a significant low-energy seismic activity, principally originated by ice creeping and basal stress at the interface between the ice and the bedrock. The geodetic stations allowed us to survey the glacier kinematics forced by the Ross Sea tides, and to infer the grounding line location. Here we show some details about data analysis and preliminary results.
Keywords: Antarctica; David Glacier; Tidal force; Geodetic observations; Seismicity
Programme: 906
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Danesi S., M. Dubbini, A. Morelli and L. Vittuari. (2008). Joint geophysical observations of ice stream dynamics (A. Capra and R. Dietrich Eds., Ed.). Bachelor's thesis, Springer-Verlag Berlin Publ., Berlin.
Abstract: Contribution
to ‘Geodetic and Geophysical Observatories in Polar Regions –
Overview in the IPY Perspective’, Springer-Verlag Berlin Publ., A.
Capra and R. Dietrich Eds.,
Programme: 906
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Danesi S., S. Bannister and A. Morelli. (2007). Repeating earthquakes from rupture of an asperity under an Antarctic outlet glacier. Earth Planet. Sci. Lett., 253, 151–158.
Abstract: doi: 10.1016/j.epsl.2006.10.023, Vol. 253
(1-2)
Programme: 906
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Grezio A., Camassi R., Danesi S., Morelli A. (2006). ANTARCTICA a natural observatory for understanding Earth. INGV/PNRA.
Abstract: published by INGV/PNRA.
Programme: 906
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Pondrelli S., L. Margheriti and S. Danesi. (2005). Seismic anisotropy beneath Northern Victoria Land from SKS splitting analysis, Antarctica. Bachelor's thesis, Springer-Verlag Berlin Heidelberg Eds, .
Abstract: Contr.
to Global Earth Sciences, Springer-Verlag Berlin Heidelberg Eds.
Programme: 906
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Faccenna, C.; Rossetti, F.; Becker, T.W.; Danesi, S.; Morelli, A. (2008). Recent extension driven by mantle upwelling beneath the Admiralty Mountains (East Antarctica). Tectonics, 27.
Abstract: Northern Victoria Land is located at the boundary between an extended, presumably hot, region (West Antarctic Rift System) and the thick, possibly cold, East Antarctic craton. The style and timing of Tertiary deformation along with relationships with the magmatic activity are still unclear, and contrasting models have been proposed. We performed structural and morphotectonic analyses at the NE termination of northern Victoria Land in the Admiralty Mountains area, where the relationship between topography, tectonics, and magmatism is expected to be well pronounced. We found evidence of two subsequent episodes of faulting, occurring concurrently with the Neogene McMurdo volcanism. The first episode is associated with dextral transtension, and it is overprinted by extensional tectonics during the emplacement of large shield alkaline volcanoes. Upper mantle seismic tomography shows that the extensional regime is limited to regions overlying a low-velocity anomaly. We interpret this anomaly to be of thermal origin, and have tested the role of large-scale upwelling on lithosphere deformation in the area. The results of this integrated analysis suggest that the morphotectonic setting of the region and the magmatism is likely the result of upwelling flow at the boundary between the cold cratonic and the hot stretched province (WARS), at work until recent time in this portion of the northern Victoria Land.
Keywords: Antarctica; continental tectonics; faulting; mantle dynamics; seismic tomography; 7230 Seismology: Seismicity and tectonics; 8010 Structural Geology: Fractures and faults; 8107 Tectonophysics: Continental neotectonics; 7270 Seismology: Tomography; 8122 Tectonophysics: Dynamics: gravity and tectonics
Programme: 906
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JJ. Leveque, A. Maggi, A. Delladio, J. Burdin, JY. Thore, A. Morelli. (2008). ConCorDia: a new, permanent seismological station in Antarctica. EGU General Assembly, Vienna, 2008.
Abstract: European Geophysical Society
Concordia (Dome C) is the site of a permanent seismic observatory station, CCD,
which has been running since 2005. The station is placed 1 km away from the inhabited
part of the base, and consists of a vault at 12 m below snow level and a shelter on
the surface. While the acquisition electronics operate at temperate conditions (0-20C)
in the shelter, the seismometers are placed in the vault at a stable temperature of -60C,
well below design specifications.
Our first policy was to run the seismometers (two Streckeisen STS-2s) at this temperature,
because heating induces small variations in temperature that in turn add noise to
the seismic signals. This policy led to a first difficulty in re-centering the instruments
at temperatures below -45C, resulting in poorly centered seismometers at the steady
state temperature of -60C. Secondly, and more importantly, the signal – of good quality
during the first few weeks/months – ultimately degraded and became useless (spurious
and frequent oscillations and spikes of unknown origin).
As of 2007, we have relaxed our no-heating policy, and are heating one of the two instruments.
In order to avoid convection which is the most likely source of temperature
perturbation, we installed our heating elements at the top of the volume in order to create
a stable stratified temperature gradient. The temperature at the base of the heated
STS-2 is now -30C. It seems, from the information we currently have available, that
the heated seismometer performs much better. We shall present a more detailed analysis
of the data from the heated and unheated systems, based on the complete 2007
dataset.
Programme: 906
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Leveque JJ, Wittlinger G, Maggi A. (2009). The ice-layer in Antarctica : preliminary results from seismology, AGU Fall Meeting, San Francisco.
Abstract: EOS, Transactions, American Geophysical Union
Programme: 906
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Souriau A, Leveque JJ, Maggi A. (2009). Seismological constraints on ice properties at Dome C, Antarctica, from H/V measurements, AGU Fall Meeting, San Francisco..
Abstract: EOS, Transactions, American Geophysical Union
Programme: 906
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