Seismic site classification of the Costa Rican Strong-Motion Network based on VS30 measurements and site fundamental period

• Published in: Earth sciences research journal 2021, Vol.25 (4), p.383-389
• Main Authors: Pinzón, Luis A., Hidalgo-Leiva, Diego A., Moya-Fernández, Aarón, Schmidt-Díaz, Victor, Pujades, Luis G.
• Format: Article
• Language: English
• Subjects: Acceleration; Accelerometers; Building codes; Classification; Ground motion; Ratios; Response spectra; S waves; Seismic velocities; Soil; Soil classification; Soil profiles; Soil properties; Spectra; Wave velocity
• ISSN: 1794-6190; 2339-3459
• DOI: 10.15446/esrj.v25n4.93927

In this paper, a new seismic site classification for the Costa Rican Strong-Motion Network (CRSMN) is proposed. The soil profile classification of the Costa Rican Seismic Code based on the average shear-wave velocity of the top 30 m (VS30) is used as a reference. The site fundamental period (Tf) is included as a parameter to complement the existing characterization. For this, the VS30 measurements from 52 accelerometric stations are related to the site fundamental period obtained through horizontal-to-vertical spectral ratios (HVSR) using ground motion records from the Costa Rican Strong-Motion Database. The H/V ratios are estimated with 5% damped acceleration response spectra and with traditional Fourier amplitude spectra from the S-wave window. From the relation between VS30 and Tf, different ranges of Tf are assigned to the existing soil profile classification and a graph with three-lines and four-areas is proposed to classify the stations of the CRSMN.