Name
Site-Specific Seismic Amplification for Improved Earthquake Early Warning
Description
A well-implemented Earthquake Early Warning (EEW) system can provide seconds to tens of seconds warning of imminent shaking due to earthquakes. EEW works by rapidly detecting and locating an earthquake using the low-amplitude, faster travelling compressional waves to predict shaking that will occur during the arrival of slower and more damaging shear waves. With the implementation of the new national EEW system in Canada, understanding the impact of site effects on ground motion at the newly deployed stations will improve alerting accuracy. This study uses mean ground motion spectral ratios (GMSR) with respect to a reference hard rock site to determine predominant site periods for Canadian National Seismic Network stations in eastern Canada. Determination of peak amplitudes from recorded earthquake spectra requires a robust earthquake catalogue at each station; therefore, the GMSR method cannot yet be applied to the newly installed EEW stations. Here, the horizontal to vertical spectral ratio (HVSR) site period is used as a proxy for GMSR, to estimate site-specific amplification at newly deployed EEW stations across eastern and western Canada. The results of this study provide site amplification factors that reflect expected ground motion at EEW sites, leading to improved alerting outcomes and better understanding of site effects on ground motion.