The seismic response of the Ortigia (Siracusa) area was stadiede aiming to test the reliability of using ambient noise recordings to define possible topographic effects. The study area is formed by a carbonate sequence whose dynamic properties were investigated through non-invasive techniques. V(S 30) of about 1000 m/s was found, that is in good agreement with an A soil category. Ambient noise was recorded in twelve sites and signals were processed through spectral ratio techniques. Directional effects were investigated as well. The results coming out from the rotation of HVNR show a clearly predominant E-W directional effect which is also confirmed by the polarization angle observed. The peaks observed in the spectral ratios, in the frequency range 1.0-2.0 Hz, are consistent with the theoretical resonance frequency expected for the Ortigia hill as topographic effects (f0 ~ 1.25 Hz).
SITE RESPONSE IN ORTIGIA PENINSULA (SIRACUSA, ITALY)
PANZERA F;LOMBARDO, Giuseppe;
2010-01-01
Abstract
The seismic response of the Ortigia (Siracusa) area was stadiede aiming to test the reliability of using ambient noise recordings to define possible topographic effects. The study area is formed by a carbonate sequence whose dynamic properties were investigated through non-invasive techniques. V(S 30) of about 1000 m/s was found, that is in good agreement with an A soil category. Ambient noise was recorded in twelve sites and signals were processed through spectral ratio techniques. Directional effects were investigated as well. The results coming out from the rotation of HVNR show a clearly predominant E-W directional effect which is also confirmed by the polarization angle observed. The peaks observed in the spectral ratios, in the frequency range 1.0-2.0 Hz, are consistent with the theoretical resonance frequency expected for the Ortigia hill as topographic effects (f0 ~ 1.25 Hz).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
