Site effect characterization in Tierra del Fuego Island with H/V spectral ratio

Abstract

Understanding and delving into the study of site effects in a region is highly important as it can reveal the main structural characteristics beneath seismic stations, which is of interest for seismic risk and/or seismic design studies. This work focuses on investigating the seismic structure of the southernmost region of Patagonia to gain insights into its evolution and current geodynamics, particularly on Tierra del Fuego Island, known for its significant seismological history. To achieve this, we analyze the near-surface crustal structure using the HVSR technique to determine resonance frequencies at different sites originated from impedance contrasts at varying depths. To characterize the site effect in the area, we examined this relationship as a function of frequency and, through inversion, obtained seismic models beneath two stations. These results improve the region's models obtained in previous studies through dispersion analysis and receiver function analysis, demonstrating an improved spatial correlation with the known tectonic features and providing valuable information for seismic hazard studies on the island.