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Babuska, V.
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Babuska, V.
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- PublicationOpen AccessTeleseismic P-residual study in the Italian region - inferences on large scale anisotropic structure of the subcrustal lithosphere(1998-04)
; ; ; ;Plomerová, J.; Geophysical Institute, Czech Academy of Sciences, Prague, Czech Republic ;Babuska, V.; UNESCO, Division of Earth Sciences, Paris, France ;Scarpa, R.; Dipartimento di Fisica, Università dell'Aquila, Coppito, L'Aquila, Italy; ; Jeffreys-Bullen (absolute) and relative P-wave travel-time residuals were analyzed over Italy and its surrounding using P arrival times from the ISC bulletins supplemented by the data from local observatories. We analyzed the travel-time station corrections by two independent methods to obtain information on lateral variations of the velocity structure over the area and a view of possible upper mantle anisotropy. In the first method, the station corrections are computed as a constant and two cosine terms with appropriate phase shifts. Besides a static term, the second method allows us to study the relative residuals in dependence both on azimuths and incidence angles and thus to investigate their spatial variations and to map lateral variations of anisotropic structure of the subcrustal lithosphere. The high and low-velocity directions inferred from the spatial distribution of the relative residuals as well as the high- and low-velocity upper mantle heterogeneities reflect the geodynamic development of the region, governed by the collision between the African and Eurasian plates152 434 - PublicationOpen AccessThe subduction structure of the Northern Apennines: results from the RETREAT seismic deployment(2006-08)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Margheriti, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Pondrelli, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Piccinini, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Piana Agostinetti, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Giovani, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Salimbeni, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Pio Lucente, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Amato, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Baccheschi, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Park, J.; Yale University, Department of Geology and Geophysics, New Haven, CT, U.S.A. ;Brandon, M.; Yale University, Department of Geology and Geophysics, New Haven, CT, U.S.A. ;Levin, V.; Rutgers University, Department of Geological Sciences, Piscataway, NJ, U.S.A. ;Plomerová, J.; Geophysical Institute, Czech Academy of Sciences, Prague, Czech Republic ;Jedlicka, P.; Geophysical Institute, Czech Academy of Sciences, Prague, Czech Republic ;Vecsey, L.; Geophysical Institute, Czech Academy of Sciences, Prague, Czech Republic ;Babuska, V.; Geophysical Institute, Czech Academy of Sciences, Prague, Czech Republic ;Fiaschi, A.; Fondazione Prato Ricerche, Prato, Italy ;Carpani, B.; ENEA, Centro Ricerche Brasimone, Camugnano (BO), Italy ;Ulbricht, P.; IRIS PASSCAL Instrument Centre, Socorro, NM, U.S.A.; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The project Retreating-trench, extension, and accretion tectonics, RETREAT, is a multidisciplinary study of the Northern Apennines (earth.geology.yale.edu/RETREAT/), funded by the United States National Science Foundation (NSF) in collaboration with the Italian Istituto Nazionale di Geofisica e Vulcanologia (INGV) and the Grant Agency of the Czech Academy of Sciences (GAAV). The main goal of RETREAT is to develop a self-consistent dynamic model of syn-convergent extension, using the Northern Apennines as a natural laboratory. In the context of this project a passive seismological experiment was deployed in the fall of 2003 for a period of three years. RETREAT seismologists aim to develop a comprehensive understanding of the deep structure beneath the Northern Apennines, with particular attention on inferring likely patterns of mantle flow. Specific objectives of the project are the crustal and lithospheric thicknesses, the location and geometry of the Adriatic slab, and the distribution of seismic anisotropy laterally and vertically in the lithosphere and asthenosphere. The project is collecting teleseismic and regional earthquake data for 3 years. This contribution describes the RETREAT seismic deployment and reports on key results from the first year of the deployment. We confirm some prior findings regarding the seismic structure of Central Italy, but our observations also highlight the complexity of the Northern Apennines subduction system.373 269 - PublicationRestrictedSeismic anisotropy beneath the Northern Apennines (Italy): Mantle flow or lithosphere fabric?(2006)
; ; ; ; ; ; ; ; ; ; ;Plomerová, J.; Geophysical Institute, Czech Acad. of Sci., Boční II, 141 31 Prague 4, Czech Republic ;Margheriti, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Park, J.; Yale University, Department of Geology and Geophysics, New Haven, USA ;Babuška, V.; Geophysical Institute, Czech Acad. of Sci., Boční II, 141 31 Prague 4, Czech Republic ;Pondrelli, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Vecsey, L.; Rutgers University, Department of Geological Sciences, NJ, USA ;Piccinini, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Levin, L.; Rutgers University, Department of Geological Sciences, NJ, USA ;Baccheschi, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Salimbeni, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; ; ; ; ; ; ; ; ; Shear-wave splitting estimates from recordings of 10 portable seismographic stations during the first year of the RETREAT seismic deployment, in combination with broadband data from the Italian national seismic network, are associated with seismic anisotropy within the upper mantle beneath the Northern Apennines. Anisotropic parameters derived from both shear-wave splitting and P travel-time residuals vary geographically and depend on event back-azimuth, reflecting complexity in the underlying mantle strain field. Variations of the splitting time delays and fast polarization seem to exclude a 2-D sublithosphere corner flow, associated with the Apennines subduction, as the main source of the inferred anisotropy. The anisotropic signal may be generated by a frozen-in fabric of the Adriatic and Tyrrhenian lithosphere domains, or by flow variations induced by episodic and fragmentary slab rollback.217 25