A technique that analyses the horizontal-to-vertical spectral ratios (HVNR) of ambient noise recordings was tested as a tool to investigate the dynamic response of landslide prone slopes to seismic shaking. Tests were conducted in landslide areas where available accelerometer recordings allowed a comparison with amplification properties observed during earthquakes. Where accelerometer data revealed the presence of directional resonance, the HVNR technique proved to be able to recognise its presence and characteristics (orientation and frequency). The actual amplification factor does not seem to be quantifiable from the spectral ratios, whose peak amplitude values show a scattering apparently depending on changeable environmental conditions. Where site response directivity is absent, the HVNR values generally do not show a common preferential orientation of strongly directional peaks, unless, occasionally, in presence of temporary active sources of polarized noise. Thus, to avoid misinterpretations we recommend HVNR measurement repetitions at different times and under different environmental conditions.
Application of ambient noise analysis for investigating site amplification properties of slopes susceptible to seismically induced failures
DEL GAUDIO, Vincenzo;
2012-01-01
Abstract
A technique that analyses the horizontal-to-vertical spectral ratios (HVNR) of ambient noise recordings was tested as a tool to investigate the dynamic response of landslide prone slopes to seismic shaking. Tests were conducted in landslide areas where available accelerometer recordings allowed a comparison with amplification properties observed during earthquakes. Where accelerometer data revealed the presence of directional resonance, the HVNR technique proved to be able to recognise its presence and characteristics (orientation and frequency). The actual amplification factor does not seem to be quantifiable from the spectral ratios, whose peak amplitude values show a scattering apparently depending on changeable environmental conditions. Where site response directivity is absent, the HVNR values generally do not show a common preferential orientation of strongly directional peaks, unless, occasionally, in presence of temporary active sources of polarized noise. Thus, to avoid misinterpretations we recommend HVNR measurement repetitions at different times and under different environmental conditions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
