Multimethod Characterization of the French-Pyrenean Valley of Bagnères-de-Bigorre for Seismic-Hazard Evaluation: Observations and Models - Archive ouverte HAL Access content directly
Journal Articles Bulletin of the Seismological Society of America Year : 2011

Multimethod Characterization of the French-Pyrenean Valley of Bagnères-de-Bigorre for Seismic-Hazard Evaluation: Observations and Models

(1) , (2) , (2) , (1) , (1) , (1) , (2) , (3) , (3) , (4) , (2) , (2)
1
2
3
4
Annie Souriau
  • Function : Author
  • PersonId : 923037
Emmanuel Chaljub
Cécile Cornou
  • Function : Author
Ludovic Margerin
Marie Calvet
Julie Maury
Marc Wathelet
  • Function : Author
Mickael Langlais
  • Function : Author
Philippe Gueguen

Abstract

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 characteriza- tion. 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 struc- ture 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.
Fichier principal
Vignette du fichier
ArticlebagnA_re-VersDef.pdf (3.27 Mo) Télécharger le fichier
Origin : Files produced by the author(s)
Loading...

Dates and versions

hal-00655919 , version 1 (03-01-2012)

Identifiers

Cite

Annie Souriau, Emmanuel Chaljub, Cécile Cornou, Ludovic Margerin, Marie Calvet, et al.. Multimethod Characterization of the French-Pyrenean Valley of Bagnères-de-Bigorre for Seismic-Hazard Evaluation: Observations and Models. Bulletin of the Seismological Society of America, 2011, 101 (4), pp.1912-1937. ⟨10.1785/0120100293⟩. ⟨hal-00655919⟩
368 View
118 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More