Reliability of combined active and passive surface wave methods

Surface wave methods, both active and passive, are often used for shallow site characterisation especially in seismic studies. They provide valuable information about the subsurface soil with relatively little economic effort. For active surveys the depth of penetration is typically limited by the amount of information in the low frequency range. Passive methods are based on the analysis of microtremors, which are characterized by an extended content of energy in the low frequency range; hence they allow for deep characterization, but typically lack resolution for shallow layers. In the present paper the combined use of active and passive data in surface wave tests is explored in order to take advantage of the complementary information given by the two methods. The experimental results for a case history, in which Down-Hole tests were available for a comparison, are presented, showing the great potential of the combined technique. Finally, the implications of data uncertainties in terms of resolution and reliability are explored using a Monte Carlo approach for the inversion process, illustrating the importance of active data to improve the characterization of shallow layers.

Surface wave me …

AUTORI: Foti S., Comina C., Boiero D.
Numero di pagine: 39

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