Publikationsdatum:
2011-12-01
Beschreibung:
Ratios of vertical-to-horizontal (V/H) ground motion are important for the computation of scenario-compatible vertical design spectra. They are therefore a crucial aspect of seismic hazard analysis. We characterize the V/H ratio at rock sites in terms of the recording site’s average quarter-wavelength velocity. A predictive equation is presented, which can be used for reconstructing the expected V/H ratio of the 5%-damped response and Fourier spectra for rock sites, given a known shear-wave velocity profile. The equation is based on the regression analysis of two datasets: one from Switzerland and one from Japan. The two datasets allow us to analyze well-characterized hard-rock sites in Switzerland using small earthquakes (Mw〉2), while the magnitude range is increased up to events of Mw 7.3 using strong-motion recordings from Japan’s KiK-net seismic network. It is shown that a correlation exists between the quarter-wavelength velocity at a given frequency and the V/H ground-motion ratio. Small differences, possibly due to velocity measurement bias or topographical and basin effects, existed when analyzing the individual regional datasets. Apart from near-source distances (R
Print ISSN:
0037-1106
Digitale ISSN:
1943-3573
Thema:
Geologie und Paläontologie
,
Physik
