GNGTS 2017 - 36° Convegno Nazionale

574 GNGTS 2017 S essione 3.1 The ambient vibrations were recorded by means of 24 bit Reftek130 data loggers coupled to three-component velocimeter with eigenfrequency of 0.2 Hz. The sampling rate was set to 250 Hz and minimum recording duration to 1 hour. We processed the data and computed the H/V curves by using the Geopsy code. Average values of the shear-wave velocity (Vs) of the basin infill deposits were estimated in the range of 600–700 m/s (Di Giulio et al., 2014). Assuming such values of Vs as representative of the average basin infill velocity, the range of possible top- bedrock depths (Z) has been estimated simply as Z = Vs/(4×f0) (Nakamura, 1989). Fig. 1 - A) TDEM and H/V measurements in the middle Aterno valley, The map also shows the main infrastructures and lifelines in the study area. B) 1-D resistivity models (solid red lines) recovered from the inversion of TDEM data and top-bedrock depth interval (solid vertical black lines) as derived from H/V curves for different top-bedrock depths: a) calibration of TDEM and H/V models with well log data (Pianola well log - b ttp://sgi.ispram b iente.it/ indagini/scheda_indagine.asp?Codice = 156784 - see Fig. 1A for well location) for shallow top bedrock depth; b) intermediate, and c) deep top-bedrock depths. Dashed red lines indicate respectively the upper and lower depths of investigation calculated for the TDEM output resistivity models (Christiansen and Auken, 2012).