Seismic ground shaking by historical earthquakes in the Firenze metropolitan area

The seismic vulnerability assessment of a complex metropolitan area depends on the seismic source, wave propagation, and site amplification, as well as seismic response of single edifices. As a first step to evaluate the seismic vulnerability of Firenze, we computed the seismic ground motion on rigid bedrock of the 1919, 6.3 Mw Mugello earthquake in Tuscany, Italy, through a stochastic finite-fault technique (EXSIM) in conjunction with the Python framework.

The theoretical shake maps, evaluated at epicentral distances ranging between 10 and 100 km, is computed from 360 synthetic waveforms and corresponding Fourier acceleration spectrum, pseudo-spectral acceleration, peak ground acceleration, and peak ground velocity in the high-frequency range (f > 1 Hz). Synthetic waveform analysis is performed to investigate the model dependance on the various input parameters and corresponding confidence levels.

Comparison between model results and shake maps obtained from historical damages was used to validate the analysis and discuss the relation between expected damages and the main seismogenic area around the city. This study is performed in the framework of the HGP project (CUP:B55F21007810001) funded within the Next Generation EU program.