Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/8836
AuthorsPrudencio, I.* 
Ibanez, J.* 
Garcia-Yeguas, A.* 
Del Pezzo, E.* 
Posadas, A. M.* 
TitleSpatial distribution of intrinsic and scattering seismic attenuation in active volcanic islands – II: Deception Island images
Issue Date2013
Series/Report no./195 (2013)
DOI10.1093/gji/ggt360
URIhttp://hdl.handle.net/2122/8836
KeywordsSeismic attenuation;
Seismic tomography
Volcano seismology
Wave scattering and diffraction
Wave propagation
Subject Classification04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy 
04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology 
04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis 
AbstractIn this work, we present regional maps of the inverse intrinsic quality factor (Qi −1), the inverse scattering quality factor (Qs −1) and total inverse quality factor (Qt −1) for the volcanic environment of Deception Island (Antarctica). Our attenuation study is based on diffusion approximation, which permits us to obtain the attenuation coefficients for every single couple source-receiver separately. The data set used in this research is derived from an active seismic experiment using more than 5200 offshore shots (air guns) recorded at 32 onshore seismic stations and four ocean bottom seismometers. To arrive at a regional distribution of these values, we used a new mapping technique based on a Gaussian space probability function. This approach led us to create ‘2-D probabilistic maps’ of values of intrinsic and scattering seismic attenuation. The 2-D tomographic images confirm the existence of a high attenuation body below an inner bay of Deception Island. This structure, previously observed in 2-D and 3-D velocity tomography of the region, is associated with a massive magma reservoir. Magnetotelluric studies reach a similar interpretation of this strong anomaly. Additionally, we observed areas with lower attenuation effects that bear correlation with consolidated structures described in other studies and associated with the crystalline basement of the area. Our calculations of the transport mean-free path and absorption length for intrinsic attenuation gave respective values of ≈950 m and 5 km, which are lower than the values obtained in tectonic regions or volcanic areas such as Tenerife Island. However, as observed in other volcanic regions, our results indicate that scattering effects dominate strongly over the intrinsic attenuation.
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