Application of numerical simulations for a tentative seismic microzonation of the city of Rome

D. Fah, C. Iodice, P. Suhadolc, G. F. Panza

Abstract


A hybrid technique, based on mode summation and finite differences, was used to silnulate the ground motion
induced in the city of Rome by possible earthquakes occurring in the main seisrnogenetic areas surrounding
the city: the Central Apennines and the Alban Hills. The results of the numerical simulations are used for a
seismic inicrozonation in the city of Rome, which can be used for the retrofitting of buildings of special social
and cultural value. On the basis of our analysis Rome can be divided into six main zones: (1) the edges and (2)
the central part of the alluvial basin of the River Tiber; (3) the edges and (4) the central part of the Paleotiber
basin; the areas outside the large basins of the Tiber and Paleotiber, where we distinguish between (5) areas
without, and (6) areas with a layer of volcanic rocks close to the surface. The strongest amplification effects
have to be expected at the edges of the Tiber basin, with maximum spectral amplification of the order of 5 to
6, and strong arnplifications occur inside the entire alluvial basin of the Tiber. The presence of a near-surface
layer of rigid material is not sufficient to classify a location as a <> when the rigid material covers
a sedimentary complex. The reason is that the underlying sedimentary complex causes amplifications at the
surface due to resonance effects. This phenomenon can be observed in the Paleotiber basin, where spectral amplifications
in the frequency range 0.4-1.0 Hz reach values of the order of 3 to 4.

Keywords


Rome;wave-propagation modelling;seismic strong ground motion;seismic microzonation

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References


DOI: https://doi.org/10.4401/ag-4079

Published by INGV, Istituto Nazionale di Geofisica e Vulcanologia - ISSN: 2037-416X