Publication Date:
2022-02-15
Description:
The within-site variability in site response is the randomness in site response at a given site from different earthquakes and is treated as aleatory variability in current seismic hazard/risk analyses. In this study, we investigate the single-station variability in linear site response at K-NET and KiK-net stations in Japan using a large number of earthquake recordings. We found that the standard deviation of the horizontal-to-vertical Fourier spectral ratio at individual sites, i.e., single-station HVSR sigma σHV,s, approximates the within-site variability in site response quantified using surface-to-borehole spectral ratios (SBSR, for oscillator frequencies higher than the site fundamental frequency) or empirical groundmotion models (GMMs). Based on this finding, we then utilize the single-station HVSR sigma as a convenient tool to study the site-response variability at 697 KiK-net and 1169 K-NET sites. Our results show that at certain frequencies, stiff, rough and shallow sites, as well as small and local events tend to have a higher σHV,s. However, when being averaged over different sites, the single-station HVSR sigma, i.e., σHV, increases gradually with decreasing frequency. In the frequency range of 0.25-25 Hz, σHV is centred at 0.23-0.43 in ln scales (a linear scale factor of 1.26-1.54) with one standard deviation of less than 0.1. σHV is quite stable across different tectonic regions, and we present a constant, as well as earthquake magnitude- and distance-dependent σHV models.
Language:
English
Type:
info:eu-repo/semantics/article
Format:
application/pdf
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