Souriau A. auteur aut IRD Chaljub E. auteur aut IRD Cornou Cécile auteur aut IRD Margerin L. auteur aut IRD Calvet M. auteur aut IRD Maury J. auteur aut IRD Wathelet Marc auteur aut IRD Grimaud F. auteur aut IRD Ponsolles C. auteur aut IRD Pequegnat C. auteur aut IRD Langlais M. auteur aut IRD Gueguen P. auteur aut IRD text journalArticle eng text/pdf born digital access A narrow rectilinear valley in the French Pyrenees, affected in the past by damaging earthquakes, has been chosen as a test site for soil response characterization. The main purpose of this initiative was to compare experimental and numerical approaches. A temporary network of 10 stations has been deployed along and across the valley during two years; parallel various experiments have been conducted, in particular ambient noise recording, and seismic profiles with active sources for structure determination at the 10 sites. Classical observables have been measured for site amplification evaluation, such as spectral ratios of horizontal or vertical motions between site and reference stations using direct S waves and S coda, and spectral ratios between horizontal and vertical (H/V) motions at single stations using noise and S-coda records. Vertical shear-velocity profiles at the stations have first been obtained from a joint inversion of Rayleigh wave dispersion curves and ellipticity. They have subsequently been used to model the H/V spectral ratios of noise data from synthetic seismograms, the H/V ratio of S-coda waves based on equipartition theory, and the 3D seismic response of the basin using the spectral element method. General good agreement is found between simulations and observations. The 3D simulation reveals that topography has a much lower contribution to site effects than sedimentary filling, except at the narrow ridge crests. We find clear evidence of a basin edge effect, with an increase of the amplitude of ground motion at some distance from the edge inside the basin and a decrease immediately at the slope foot. specialized 066 101 4 1912-1937 2011 0037-1106 https://www.documentation.ird.fr/hor/fdi:010053760 10.1785/0120100293 0037-1106 [F B010053760] https://www.documentation.ird.fr/hor/fdi:010053760 https://www.documentation.ird.fr/intranet/publi/2011/08/010053760.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2011-09-01 2017-08-23 fdi:010053760 fre