On the inadequacy of JICA seismic site response estimation in Tehran: new developed shear wave velocity profiles for the 1D seismic response analysis in Tehran sedimentary basin

Soltani, Saeed; Haghshenas, Ebrahim; Guillier, Bertrand; Cornou, Cecile

doi:10.48303/jsee.2024.2039693.1122

On the inadequacy of JICA seismic site response estimation in Tehran: new developed shear wave velocity profiles for the 1D seismic response analysis in Tehran sedimentary basin

Articles in Press

Document Type : Research Article

Authors

Saeed Soltani ¹

Ebrahim Haghshenas ²

Bertrand Guillier ³

Cecile Cornou ³

¹ IIEES UGA (Grenoble Alpes University)

² IIEES

³ UGA

10.48303/jsee.2024.2039693.1122

Abstract

The amplification of ground motion at the surface is significantly influenced by soil properties, and constructing a reliable shear wave velocity model down to the seismic bedrock depth is indeed the key factor in determining a reliable seismic response. In Tehran, the previous site’s seismic response analysis relied solely on very shallow geotechnical measurements up to the engineering bedrock. The results showed the negligible amplification in frequencies higher than 1Hz, what was very different with the results of experimental amplification ratios, obtained using the site to reference method on real earthquake data (Haghshenas, 2005). The latter indicated a high level of amplification for a broad range of frequencies. In present study, we recalculated simple one-dimensional seismic responses for Tehran, using the newly developed deep shear wave velocity models, developed by Soltani et al. (2024; submitted), to evaluate whether these models accurately represents the actual site amplification. The results indicate that the relative differences between newly 1D calculated transfer functions and experimental observation are less than 20%. However, in certain stations, mostly in the central part of the basin, these differences exceeded 20%, which can be attributed to the inherent multi-dimensional behavior of the Tehran basin.

Keywords

Tehran basin

Array measurements

1D site response

Subjects