Correlation between H/V Spectral Ratio Shape and Subsoil Stratigraphy in 10 Selected Sites

Abstract

Once the horizontal to vertical technique is applied to ambient vibrations, it is possible that peaks are not well identified. These peaks are usually associated to significant contrasts between soil and bedrock, and this condition may not be presented in all sites. However, the shape of graphics could give additional valuable information about specific characteristics of the soil profile, such as: slope of the bedrock, inversion of shear velocities between successive soil layers, homogeneity of materials, etc. This research intends to correlate the shape of the H/V graphics with the available geophysical information for 10 previously characterized sites. Similar studies proposed by other authors are considered. Ambient vibrations were registered using a triaxial
seismograph. The ratio of the averaged horizontal to vertical spectra were obtained. These plots were related to the site stratigraphy and four cases were well identified: pointed peak, wide peak, double peak and flat graph.