EGU23-6655
https://doi.org/10.5194/egusphere-egu23-6655
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Vs model for Oran city, obtained by joint-inversion of dispersion and HVSR curves

ahmed saadi1,2, Abdelouahab Issaadi1,2, Fethi Semmane2, Abdelkrim Yelles–Chaouche2, Juan José Galiana-Merino1, Khalissa Layadi2, and Redouane Chimouni2
ahmed saadi et al.
  • 1University Institute of Physics Applied to Sciences and Technologies, University of Alicante, Crta. San Vicente Del Raspeig, s/n, 03080, Alicante, Spain
  • 2Centre de Recherche en Astronomie, Astrophysique et Géophysique (CRAAG), 16340, Algiers, Algeria

Abstract

The city of Oran, which is located in the northwest of Algeria, in the Lower-Cheliff basin, has experienced several earthquakes in the past. Therefore, the characterization of its subsurface is crucial for a better assessment of the seismic hazard. Single-station ambient vibration measurements at 193 sites and array measurements at 15 sites have been analyzed with HVSR and F-K techniques, respectively, for the soil investigation.The HVSR curves showed a variation of the fundamental frequency peak between 0.3 and 7.4 Hz, increasing from east to west, and reaching a maximum amplitude of ~6. Rayleigh wave dispersion curves were obtained by F-K analysis. Joint-inversion of the dispersion and HVSR curves provided a shear wave velocity model and an estimate of the bedrock depth. The models showed 3 layers of sediments overlying the bedrock. The shear-wave velocity (Vs) of the softer sediments varies between 280 and 580 m/s, and at bedrock it varies between 1600 and 2500 m/s. The latter reached a maximum depth of 1050 m northeast of the city. In addition, these results were used to calculate the soil vulnerability factor (Kg), and the Vs30 in the entire area. Finally, a soil classification and a regression law between the fundamental frequency and the depth were proposed for the whole city.

How to cite: saadi, A., Issaadi, A., Semmane, F., Yelles–Chaouche, A., Galiana-Merino, J. J., Layadi, K., and Chimouni, R.: Vs model for Oran city, obtained by joint-inversion of dispersion and HVSR curves, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6655, https://doi.org/10.5194/egusphere-egu23-6655, 2023.