GNGTS 2013 - Atti del 32° Convegno Nazionale

Scholz C.H., Sykes L.R. and Aggarwal Y.P.; 1973: Earthquake prediction: a physical basis. Science, 181, 803-810. Thomas D.; 1988: Geochemical precursors to seismic activity, Pure Appl. Geophys., 126, 241-265. Toutain J.P. and Baubron J.C.; 1999: Gas geochemistry and seismotectonics: a review. Tectonophysics, 304, 1-27. Wakita H.;1975: Water wells as possible indicators of tectonic strain. Science 189, 553-555. Ulomov V.I., and Mavashev; 1967: Forerunners of the Taskent earthquake. Izvestia Akadamiyi Nauk Uzbeckistan SSR, 188-200. Seismic amplification map for some areas in the Northern Italy A. Rebez 1 , G. Di Capua 2 , M. Santulin 1 , A. Tamaro 3 1 OGS, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Trieste, Italy 2 INGV, Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy 3 PhD student of Udine University at OGS, Trieste, Italy Foreword. In this report, we illustrate soil hazard evaluations in the test area Lombardia, Emilia-Romagna, Veneto, Friuli Venezia Giulia regions developed in the frame of DPC- INGV-S2 Project “Constraining observations into Seismic Hazard. The work in the Task 4 “Site-specific hazard assessment in priority areas” were developed using geological data at national scale 1:100,000 a more dense hazard parameters grid (0.02°) was developed to better fit with this more detailed scale. In the second part of this report, the comparison between site-specific seismic hazard for two smaller test zones (Modena and Udine), obtained from geological data at national scale (1:100,000) and from more detailed geological maps (1:50,000), are presented. Seismic amplification map (Lombardia, Emilia-Romagna, Veneto, Friuli Venezia Giulia regions), based on regional geological data. In the present study the lithological amplification factors (AFs) and geological data at a national scale (1:100,000), provided by INGV-ISPRA Fig. 1a - Di Capua et al. , 2011) has been used. We considered necessary to process the data using a more dense grid of 0.02° step because for the study area (Northern Italy: Lombardia, Emilia-Romagna, Veneto, Friuli Venezia Giulia regions) only a 0.05° step data grid (Fig. 1b) was available (a g , F 0 , T c * for 30, 50, 72, 101, 140, 201, 475, 975 and 2475-year return periods, Tab. 1) from the official database of the NTC 2008 (yellow symbols in Fig. 1b). For our purposes we discretized the cited hazard parameters to a 0.02° grid. Tab. 1 – Spectral parametres NTC 2008. An example of the area interpolation of F 0 data (parameter used to compute the S s – stratigraphic amplification factor, see Tab. 2). It was then performed a resampling the F 0 data on the 0.02° grid. The same resampling procedure has been applied to a g values. Tab. 2 – Stratigraphic amplification (NTC 2008). Soil type S s A 1.00 B 1.00 ≤ 1.40-0.40 F o a g / g ≤ 1.20 C 1.00 ≤ 1.70-0.60 F o a g / g ≤ 1.50 D 0.90 ≤ 2.40-1.50 F o a g / g ≤ 1.80 E 1.00 ≤ 2.00-1.10 F o a g / g ≤ 1.60 119 GNGTS 2013 S essione 2.1