Publication Date:
2017-04-04
Description:
Paleoseismic evidence and seismic-hazard analysis suggest that the city
of Rome, Italy, has experienced considerable earthquake ground motion since its
establishment more than 2000 years ago. Seismic hazards in Rome are mainly associated
with two active seismogenic areas: the Alban Hills and the Central Apennines
regions, located about 20 km southeast and 80–100 km east of central Rome.
Within the twentieth century, M 6.8 and M 5.3 earthquakes in the Apennines and the
Alban Hills, respectively, have generated intensities up to Mercalli-Cancani-Sieberg
scale (MCS) VII in the city. With a lack of strong-motion records, we have generated
a 3D velocity model for Rome, embedded in a 1D regional model, and estimated
long-period ( 1 Hz) ground motions for such scenarios from finite-difference simulations
of viscoelastic wave propagation. We find 1-Hz peak ground velocities
(PGVs) and peak ground accelerations (PGAs) of up to 14 cm/sec and 44 cm/sec2,
respectively, for a M 5.3 Alban Hills scenario, largest near the northwestern edge of
the Tiber River. Our six simulations of a M 7.0 Central Apennine scenario generate
0.5-Hz PGVs in Rome of up to 9 cm/sec, as well as extended duration up to 60 sec.
The peak motions are similar to, but the durations much longer than those from
previous studies that omitted important wave-guide effects between the source and
the city. The results from the two scenarios show that the strongest ground-motion
amplification in Rome occurs in the Holocene alluvial areas, with strong basin edge
effects in the Tiber River valley. Our results are in agreement with earlier 2D SHwave
results showing amplification of peak velocities by up to a factor of 2 in the
alluvial sediments, largest near the contact to the surrounding Plio-Pleistocene formations.
Our results suggest that both earthquakes from the Alban Hills and the
Central Apennines regions contribute to the seismic hazards in Rome. Although
earthquakes from the former area may generate the larger peak motions, seismic
waves from the latter region may generate ground motions with extended durations
capable of causing significant damage on the built environment.
Description:
Published
Description:
133-146
Description:
JCR Journal
Description:
reserved
Keywords:
Ground-Motion
;
3-D
;
04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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