Research Information System
Soils and Foundations, vol.65, no.4, 2025 (SCI-Expanded, Scopus)
Investigating the seismic response of earth embankment dams is crucial for assessing the safety of existing dams and guiding new design procedures. The dam fundamental frequency (f0) is a critical parameter in the dynamic response of dams and can be evaluated using seismic recordings through Horizontal-to-Vertical Spectral Ratio (HVSR) and Standard Spectral Ratio (SSR) methods. This study focuses on assessing the vibration characteristics of Briones Dam, a 78 m-tall earth embankment dam located in the Bay Area in Northern California. First, earthquake-based Horizontal-to-Vertical Spectral Ratio (eHVSR) was estimated by dividing the horizontal records by the vertical components, and the SSR was determined by comparing crest recordings with those from the abutment. Additionally, a field test program was conducted to collect ambient noise measurements at Briones Dam, allowing for the calculation of microtremor-based HVSR. The fundamental frequency was estimated using three empirical methods: mHVSR (0.7–1 Hz), eHVSR (0.9–1.1 Hz), and SSR (1.2 Hz). The median fundamental frequency of the dam is estimated to be approximately 1 Hz at the center of the dam crest. The slight variations among these three methods suggest the need for further investigations that consider the geological and geotechnical conditions of the dam.