WITHDRAWN Using Horizontal-to-vertical Spectral Ratio to Characterize Landslides in Complex Terrain
Description:
WITHDRAWN The horizontal-to-vertical spectral ratio (HVSR) technique is popular within the earthquake community for site characterization. This method uses the ratio between seismic noise or earthquake recordings on horizontal and vertical components to estimate fundamental frequency, site amplification, and derive sediment thickness using a known shear-wave velocity. The method can also be used for other purposes, such as estimating the depth of landslide slip surfaces where fractured, broken material slides on a generally intact substrate. Community standards for HVSR are mainly established for simple, 1D-varying subsurface compositions. Interpretation is less straightforward in more complex terrain that characterizes many landslide settings. There is a need to better understand how to use and interpret HVSR results in these geologically complex settings because the technique can provide useful information at a lower cost, and in a less invasive way, than other geophysical and geotechnical approaches. In this study, we apply the HVSR technique to characterize landslides of varying structural complexity: the Slumgullion slow-moving landslide near Lake City, Colorado; the Bald Eagle sackung near Leadville, Colorado; and two landslides triggered by the February 6, 2023, Türkiye earthquake sequence. We installed one or more 3-component seismometers at each site and conducted rock drops to roughly estimate shear-wave velocity using direct wave arrival times where pre-existing measurements were unavailable. We find that some sites have a single, high-amplitude HVSR peak, while other sites have more complicated HVSR curves with multiple, lower-amplitude peaks. We compare the HVSR curves at the sites, explore the source of their varying degrees of complexity using simple modeling, and interpret the results of each site in context of other available information to characterize the landslide geometry. Through this work, we aim to better understand the usage of the HVSR technique for landslides and other complex geologic settings.
Session: Geophysics in a Changing World: Monitoring Applications from Seismology and Beyond [Poster]
Type: Poster
Date: 4/15/2025
Presentation Time: 08:00 AM (local time)
Presenting Author: Elaine
Student Presenter: No
Invited Presentation:
Poster Number: 46
Authors
Elaine Collins Presenting Author Corresponding Author ecollins@usgs.gov U.S. Geological Survey |
Kate Allstadt kallstadt@usgs.gov U.S. Geological Survey |
Jeffrey Coe jcoe@usgs.gov U.S. Geological Survey |
|
|
|
|
|
|
WITHDRAWN Using Horizontal-to-vertical Spectral Ratio to Characterize Landslides in Complex Terrain
Session
Geophysics in a Changing World: Monitoring Applications from Seismology and Beyond