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Francesco Pio Lucente, INGV (Italy)
Massimo Di Bona, INGV (Italy)
Davide Piccinini, INGV (Italy)
Vadim Levin, Rutgers University (United States)
Jeffrey Park, Yale University (United States)
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We estimate the sublithospheric mantle seismic attenuation beneath the northern Apennines region (Italy), by analysing the P-wave spectra from teleseismic events recorded at the temporary broadband seismic network deployed during the RETREAT (Retreating-TRrench, Extension, and Accretion Tectonics) project. We analyze P waves generated by moderate to large (MW > 5.5) teleseismic earthquakes at distances between 25° and 105°. We chose sub-crustal earthquakes (>50 km) so that the direct P wave arrivals are not complicated by surface reflections (i.e., pP, sP) within the analysis time window. For each earthquake, we compute the ratio between the spectrum at each station and the average spectrum, in order to estimate t* residuals from the spectral ratio decay. We perform the analysis by using different time window durations with the purpose of limiting possible effects from crustal seismic waves reverberations. By correlating the attenuation estimates and the velocity structure from the existing tomographic models, we can make some inferences on the thermal state of the sublithospheric mantle, and on the physical properties of the tectonic elements which constitute the subduction system in the region.
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