Determination of the shear wave velocity structure of substations by the HVSR inversion method using broadband and strong ground motion earthquake data in the Lake Van region, eastern Türkiye

Abstract

In this research, the horizontal-to-vertical spectral ratio analysis and the Monte-Carlo inversion algorithm are applied to calculate the substations shear wave velocity structure beneath the Lake Van region. To discover the variation of shear wave velocity, the local earthquakes recorded on 15 strong ground motions and 14 broadband stations, located on dissimilar geological units, are used. The most important aim of this investigation is to reveal the geological structure and bedrock depths beneath each station. For this purpose, two-dimensional cross-sections are generated from velocity models in different directions. The average bedrock depth variation is determined at 10 m and 250 m as a result of the horizontal-to-vertical spectral ratio inversions at the earthquake stations in the region. The deepest bedrock depths are calculated at the earthquake stations close to the settlements in the study area. These depth variations are interpreted as the local site effects of possible destructive and big earthquakes that may be a factor increasing the damage ratio in these regions.