Search results for "Subduction Zone Processes"
showing 3 items of 3 documents
Seismic velocity structures of Southern Italy from tomographic imaging of the Ionian slab and petrological inferences.
2012
International audience; In this study we have determined detailed Vp and Vs seismic velocity models of the Ionian lithosphere subducting beneath the Tyrrhenian basin and of the surrounding mantle, by applying a post-processing technique to a large sample of local earthquake tomography studies. Our seismic velocity models permit us to infer the presence of low velocity anomalies within the slab, which we interpret as regions that are partially hydrated by fluids released during the subduction process. A petrological interpretation of the velocity anomalies gives new details on the magmatism of the volcanic Aeolian arc. Furthermore our velocity models provide a more detailed description of th…
Turmoil at Turrialba Volcano (Costa Rica): Degassing and eruptive processes inferred from high-frequency gas monitoring.
2016
Abstract Eruptive activity at Turrialba Volcano (Costa Rica) has escalated significantly since 2014, causing airport and school closures in the capital city of San José. Whether or not new magma is involved in the current unrest seems probable but remains a matter of debate as ash deposits are dominated by hydrothermal material. Here we use high‐frequency gas monitoring to track the behavior of the volcano between 2014 and 2015 and to decipher magmatic versus hydrothermal contributions to the eruptions. Pulses of deeply derived CO2‐rich gas (CO2/Stotal > 4.5) precede explosive activity, providing a clear precursor to eruptive periods that occurs up to 2 weeks before eruptions, which are acc…
Hyper-extended rifted margin in the Tyrrhenian Sea, upper plate of the Ionian subduction zone
2011
The Tyrrhenian Sea is a Miocene to Present back-arc basin developed in the upper plate of the Ionian subduction zone. Refraction seismic data indicate that the central sector of the Marsili Basin is a zone of thin crust ∼7 km thick compatible with its oceanic origin (Steinmetz et al., 1983). Conventional models rather define a Continent-Ocean Transition (COT) with normal oceanic crust (i.e. Finetti et al., 2005). This does not seem to be the case for the whole Tyrrhenian Basin. Serpentinized peridotites, emplaced during Pliocene, have been drilled at ODP Site 651 (Sartori et al. 2004). The W Calabria segment of the Tyrrhenian continental margin is peculiar as seismic data has excluded the p…