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Preliminary Site Characterization for Earthquake Hazard Assessment Using Ambient Vibration Techniques in Haines Junction, Yukon

Description: 

In this paper, regional mapping of soil stiffness is carried out to improve the understanding of seismic hazards in southwest Yukon, Canada, where local amplification hazards are largely unknown. Ambient vibration (AV) measurements record microtremor seismic noise at broadband frequencies (0.1-128 Hz) and are used to calculate the horizontal-to-vertical spectral ratio and identify resonant frequencies at sites. In situ estimation of fundamental frequency f₀ is used to characterize sites and map local site amplification hazards.

We present preliminary site characterization using a combination of array and single station AV measurements from 23 sites in Haines Junction, Yukon. Fundamental frequencies ranging from 0.3-0.8 Hz are identified at the sites. The preliminary results suggest lateral spatial variation in fundamental frequencies, with higher frequencies identified north of Haines Junction and lower frequencies identified in south-central Haines Junction. We attribute these observations to the basin of the Dezadeash River. Identification of discrete layering in the shallow subsurface (~2.5-12 m depth) at some sites suggests the presence of an active permafrost layer. Lateral heterogeneity is found across some sites, potentially the result of either near-surface (active layer) or deeper (depth to bedrock) lateral variability.

Session: How Well Can We Predict Broadband Site-Specific Ground Motion and Its Spatial Variability So Far? [Poster Session]

Type: Poster

Date: 5/1/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Tess

Student Presenter: Yes

Invited Presentation: 

Authors