TY - JOUR
T1 - Frequency-dependent multi-offset phase analysis of surface waves: an example of high-resolution characterization of a riparian aquifer
AU - Vignoli, Giulio
AU - Gervasio, Isabella
AU - Brancatelli, Giuseppe
AU - Boaga, Jacopo
AU - Della Vedova, Bruno
AU - Cassiani, Giorgio
N1 - Publisher Copyright:
© 2015 European Association of Geoscientists & Engineers.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - Multi-offset phase analysis of seismic surface waves is an established technique for the extraction of dispersion curves with high spatial resolution and, consequently, for the investigation of the subsurface in terms of shear wave velocity distribution. However, field applications are rarely documented in the published literature. In this paper, we discuss an implementation of the multi-offset phase analysis consisting of the estimation of the Rayleigh wave velocity by means of a moving window with a frequency-dependent length. This allows maximizing the lateral resolution at high frequencies while warranting stability at the lower frequencies. In this way, we can retrieve the shallow lateral variability with high accuracy and, at the same time, obtain a robust surface-wave velocity measurement at depth. In this paper, we apply this methodology to a dataset collected for hydrogeophysical purposes and compare the inversion results with those obtained by using refraction seismics and electrical resistivity tomography. The surface-wave results are in good agreement with those provided by the other methods and demonstrate a superior capability in retrieving both lateral and vertical velocity variations, including inversions. Our results are further corroborated by the lithological information from a borehole drilled on the acquisition line. The availability of multi-offset phase analysis data also allows disentangling a fairly complex interpretation of the other geophysical results.
AB - Multi-offset phase analysis of seismic surface waves is an established technique for the extraction of dispersion curves with high spatial resolution and, consequently, for the investigation of the subsurface in terms of shear wave velocity distribution. However, field applications are rarely documented in the published literature. In this paper, we discuss an implementation of the multi-offset phase analysis consisting of the estimation of the Rayleigh wave velocity by means of a moving window with a frequency-dependent length. This allows maximizing the lateral resolution at high frequencies while warranting stability at the lower frequencies. In this way, we can retrieve the shallow lateral variability with high accuracy and, at the same time, obtain a robust surface-wave velocity measurement at depth. In this paper, we apply this methodology to a dataset collected for hydrogeophysical purposes and compare the inversion results with those obtained by using refraction seismics and electrical resistivity tomography. The surface-wave results are in good agreement with those provided by the other methods and demonstrate a superior capability in retrieving both lateral and vertical velocity variations, including inversions. Our results are further corroborated by the lithological information from a borehole drilled on the acquisition line. The availability of multi-offset phase analysis data also allows disentangling a fairly complex interpretation of the other geophysical results.
KW - Electrical resistivity tomography
KW - Multi-offset phase analysis
KW - Rayleigh wave
KW - Refraction seismics
KW - Surface wave
UR - http://www.scopus.com/inward/record.url?scp=84955172416&partnerID=8YFLogxK
U2 - 10.1111/1365-2478.12256
DO - 10.1111/1365-2478.12256
M3 - Article
SN - 0016-8025
VL - 64
SP - 102
EP - 111
JO - Geophysical Prospecting
JF - Geophysical Prospecting
IS - 1
ER -