GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 2.1 GNGTS 2023 RESULTS A summary of the number of ground motion recordings of the composite accelerometric dataset is reported below: ● ESM: o 6296 records related to 255 earthquakes recorded from pairs of stations in A-B soil classes o 3504 records related to 189 earthquakes recorded from pairs of stations in A-C soil classes o 552 records related to 77 earthquakes recorded from pairs of stations in A-D soil classes o 789 records related to 92 earthquakes recorded from pairs of stations in A-E soil classes ● Kik-Net : o 112345 records related to 6419 earthquakes recorded from pairs of stations in A-B soil classes o 51954 records related to 5840 earthquakes recorded from pairs of stations in A-C soil classes o 3062 records related to 2369 earthquakes recorded from pairs of stations in A-D soil classes ● PEER – NGA: o 49764 records related to 186 earthquakes recorded from pairs of stations in A-B soil classes o 26981 records related to 176 earthquakes recorded from pairs of stations in A-C soil classes o 2926 records related to 21 earthquakes recorded from pairs of stations in A-D soil classes To better constrain the accelerometric dataset and reduce dispersion of the data, the following criteria were enforced: ● Earthquake magnitude M w >4.0; focal depth < 35 km. ● Recording stations free surface condition; flat topography site; geotechnical characterization of the recording stations based on documented geophysical tests; sensor location in proximity of the ground level. ● Other conditions horizontal peak ground acceleration (PGA) recorded at the outcropping bedrock station > 0.02g; epicentral distance < 50 km; intra-distance between the station located at the ground surface and that placed at the outcropping bedrock < 20km. A proposed set of soil factors for soil categories B, C, D, E to be used for the definition of horizontal seismic action according to the simplified approach of NTC18 have been defined, Figure 3 reports the preliminary results for soil category B. Preliminary relationships of soil factors Ss as a function of PGA, spectral acceleration at short and intermediate oscillator period have been proposed according to the soil parameters defined in the update of Eurocode 8 Part 1. The authors would like to remark that the results presented in this conference paper are preliminary as the study is still underway.