Author: La Hamimu, Mohd Nawawi,Jamhir
Safani | Size: 1.5 MB | Format: PDF | Quality: Original preprint |
Publisher: Journal of Geophysics and Engineering, Volume 8, Number 2 |
Year: June 2011 | pages: 11 | ISSN: 1742-2132

Inversion codes based on a modified genetic algorithm (GA) have been
developed to invert multimode Love wave dispersion curves. The multimode
Love wave dispersion curves were synthesized from the profile
representing shear-wave velocity reversal using a full SH (shear
horizontal) waveform. In this study, we used a frequency–slowness
transform to extract the dispersion curve from the full SH waveform.
Dispersion curves overlain in dispersion images were picked manually.
These curves were then inverted using the modified GA. To assess the
accuracy of the inversion results, differences between the true and
inverted shear-wave velocity profile were quantified in terms of
shear-wave velocity and thickness errors, ES and EH. Our numerical
modeling showed that the inversion of multimode dispersion curves can
significantly provide the better assessment of a shear-wave velocity
structure, especially with a velocity reversal profile at typical
geotechnical site investigations. This approach has been applied on
field data acquired at a site in Niigata prefecture, Japan. In these
field data, our inversion results show good agreement between the
calculated and experimental dispersion curves and accurately detect low
velocity layer targets.