Publication Date:
2017-04-04
Description:
Three sites of the Italian Strong Motion Network (RAN) have been selected for detailed S-wave
profiling, using both borehole and surface wave seismic methods. At these sites, the presence of
stiffness contrasts within the soil column is found to influence the surface wave propagation profoundly.
Advanced aspects in surface wave inversion such as resolution, accuracy and higher-mode
interpretation must be properly taken into account to obtain realistic results from the surface wave
dispersion observations. The possibility of mode misidentification and the loss of resolution with
depth in surface wave interpretation are explored using synthetic modelling together with active and
passive seismic data sets. With high stiffness contrasts, the possibility of mode jumps and higher
mode dominance over specific frequency ranges is very probable. This is true also for normally
dispersive sites, where the shear velocity increases with depth, though higher mode dominance is
recognized as more common in the case of a shear-wave velocity inversion within the soil column
and the sensitivity of the dispersion curves with respect to those layers beneath the low-velocity
zone may be significantly reduced. Pitfalls in the inversion resulting from mode misidentification
can be avoided by investigating the effective phase velocity distribution, using active data sets and
full waveform seismic modelling. When an unambiguous modal identification is achieved, the
results obtained by surface wave inversion are very satisfactorily consistent with borehole data.
Description:
Published
Description:
75-94
Description:
4.1. Metodologie sismologiche per l'ingegneria sismica
Description:
JCR Journal
Description:
restricted
Keywords:
MASW, Borehole
;
04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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