G. Ferretti, M. Massa, L. Isella, and C. Eva
Site-amplification effects based on teleseismic wave analysis; the case of the Pellice Valley, Piedmont, Italy
Bulletin of the Seismological Society of America (April 2007), 97(2):605-613

Abstract:
The investigation of local amplification phenomena by seismic signal analysis is a fundamental step in carefully defining the seismic response of an area. In this study we investigate the use of teleseismic recordings in assessing seismic- wave amplification in the Pellice Valley (northwestern Alps, Italy). Assuming that teleseismic P waves are sensitive to the deep structure of a basin, we deal with the computation of horizontal-to-vertical spectral ratios (HVSRs) and with the estimate of teleseismic P-wave arrival time delays and P-wave amplifications with respect to a reference site. The reliability of the HVSR results obtained by considering teleseismic signals is confirmed by the agreement with the results coming from both the HVSR of noise and HVSR of S wave of local events methods. Strong correlation between the P-wave arrival time delays and the relative P-wave amplifications with respect to thickness of the low-velocity layers and the geometry of the bedrock is found.