Horizontal-to-Vertical Spectral Ratio (HVSR) Passive Seismic at the Callahan Mine Superfund Site in Brooksville, Maine: May 2017
Horizonal-to-vertical spectral ratio seismic
Dates
Publication Date
2020-08-11
Start Date
2017-05
End Date
2017-05
Citation
Johnson, C.D., White, E.A., Phillips, S.N., Pappas, K.L, and Degnan, J.R., 2020, Borehole, Surface and Water-Borne Geophysical Surveys at the Callahan Mine Superfund Site in Brooksville, Maine: October 2016 to July 2018: U.S. Geological Survey data release, https://doi.org/10.5066/P9QS925T.
Summary
The horizontal-to-vertical spectral ratio (HVSR) method is a passive seismic technique that uses a three-component seismometer to measure the vertical and horizontal components of ambient seismic noise. Seismic noise in the range of ~0.1 to 1 Hertz (Hz) is caused by ocean waves, large regional storms, and tectonic sources. A resonance frequency (f0) is induced in the unconsolidated when there is a substantial contrast (greater than 2:1) in shear-wave acoustic impedance between the overburden and the bedrock. The f0 is determined from the analysis of the spectral ratio of the horizontal and vertical components of the seismic data. The thickness of the overburden can be related to the f0. In general, lower f0 relates to thicker sediments, [...]
Summary
The horizontal-to-vertical spectral ratio (HVSR) method is a passive seismic technique that uses a three-component seismometer to measure the vertical and horizontal components of ambient seismic noise. Seismic noise in the range of ~0.1 to 1 Hertz (Hz) is caused by ocean waves, large regional storms, and tectonic sources. A resonance frequency (f0) is induced in the unconsolidated when there is a substantial contrast (greater than 2:1) in shear-wave acoustic impedance between the overburden and the bedrock. The f0 is determined from the analysis of the spectral ratio of the horizontal and vertical components of the seismic data. The thickness of the overburden can be related to the f0. In general, lower f0 relates to thicker sediments, and higher f0 relates to relatively thinner overburden. At the former Callahan MIne site the resonance frequency can be related to the depth of the overburden using an average shear-wave velocity that is measured or estimated from locations where there is a known depth to rock and/or using a direct measurement of the shear-wave velocity.
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HVSR_Callahan-Mine.xml Original FGDC Metadata
View
13.79 KB
application/fgdc+xml
CallahanMine-HVSR.zip
10.23 MB
application/zip
HVSR_DataDictionary.pdf
81.21 KB
application/pdf
GoogleEarth_Image of HVSR locations Callahan-Mine.jpg “Image showing locations of HVSR measurements in Brooksville, Maine”
243.55 KB
image/jpeg
ReadMe_HVSR_Callahan-Mine.txt
4.95 KB
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HVSR-archive-notes_Callahan-Mine.pdf
118.25 KB
application/pdf
Purpose
The geophysical data were collected to characterize mine waste and glaciomarine deposits in and around the site of the former Callahan Mine in Brooksville, Maine. These passive seismic data can be used to estimate the thickness of the overburden materials over bedrock.
Preview Image
Image showing locations of HVSR measurements in Brooksville, Maine