GNGTS 2016 - Atti del 35° Convegno Nazionale

GNGTS 2016 S essione 3.1 519 bedrock consisting of Lower Miocene calcarenite. After drilling, several holes have been used for Vs estimates through SDMT test (S1-S2), cross-hole seismic (S3-S4) or downhole seismic (S6-S8) methods. Conclusions. The results of the interpretation of the seismic lines, integrated by borehole stratigraphic and geotechnical data, may be summarized in the identification of two main horizons corresponding to the main lithological discontinuities. More precisely, the shallowest horizon, located to the top of the intermediate seismo-stratigraphic unit, likely corresponds to the litostratigraphic boundary between the coarse deposits of the Middle Plesistocene L’Aquila breccia and the fine grained deposits of the Calabrian fluvial cycle (Madonna della Strada Synthem). The position and geometry of this horizon is well constrained by the borehole data. The other important horizon is located at the top of the lower seismo-stratigraphic unit (C). This could correspond to the top of the Meso-Cenozoic carbonate bedrock, which has been intercepted at the borehole S3. Data from the boreholes have allowed to constrain the depths of these two main horizons and their geometry. The in-progress combined approach to data collection and analysis may give useful information to improve the subsoil model for the seismic site response estimation and the Seismic Hazard evaluation of L’Aquila historical downtown. References Amoroso S., Del Monaco F., Di Eusebio F., Monaco P., Taddei B., Tallini M., Totani F., Totani G.; 2010: Campagna di indagini geologiche, geotecniche e geofisiche per lo studio della risposta sismica locale della città dell’Aquila: la stratigrafia dei sondaggi (Giugno - Agosto 2010) . Report CERFIS n. 1, http://www.cerfis.it/en/download/cat_ view/67-pubblicazioni-cerfis/68-reports. Del Monaco F., Tallini M., De Rose C., Durante F.; 2013: HVNSR survey in historical downtown L’Aquila (central Italy): site resonance properties vs. subsoil model . Engineering Geology, 158 , 34-47. Fig. 2 – 3D model of the L’Aquila area. a) digital elevation model of the Aterno R. valley with the position of the seismic lines and boreholes used in in this work; b) 3D visualization of the seismic lines.