DOI: 10.5066/p9li7ccr
title: Horizontal-to-Vertical Spectral Ratio and Depth-to-Bedrock Data for Saline-Groundwater Investigation in the Genesee Valley, New York, October-November 2016 and 2017

description: In October and November of 2016 and 2017, the U.S. Geological Survey collected horizontal-to-vertical spectral ratio (HVSR) data at 104 sites in the Genesee Valley, Livingston County, New York as part of a saline-groundwater investigation in cooperation with the New York State Department of Environmental Resources. The HVSR technique, commonly referred to as the passive-seismic method, is used to estimate the thickness of unconsolidated sediments and the depth to bedrock (Lane and others, 2008). The passive-seismic method uses a single, broad-band three-component (two horizontal and one vertical) seismometer to record ambient seismic noise. In areas that have a strong acoustic contrast between the bedrock and overlying sediments, the seismic noise induces resonance at frequencies that range from about 0.3 to 40 hertz (Hz). The ratio of the average horizontal-to-vertical spectrums produces a spectral-ratio curve with peaks at fundamental and higher-order resonance frequencies. The spectral ratio curve (the ratio of the averaged horizontal-to-vertical component spectrums) is used to determine the fundamental resonance frequency that can be used along with an average shear-wave velocity or a power-law regression equation to estimate sediment thickness and depth to bedrock (Lane and others, 2008; Brown and others, 2013; Chandler and others, 2014; and Johnson and Lane, 2016). The HVSR data presented in this data release were collected at each site for 30 minutes using a Tromino Model TEP-3C three-component seismometer (1). The data were processed with Grilla 2011 version. 6.1 software1 to 1) remove anthropogenic noise, 2) convert the time-domain data to frequency domain, 3) compute and plot the spectral ratio curve, and 4) determine the resonance frequency. This data release presents the resonance frequency peaks identified from the HVSR measurements. Also presented are reported depth-to-bedrock data for wells located at or near HVSR data-collection sites in the Genesee Valley for use in the development of a local regression equation that relates the resonance frequency peak to the depth to bedrock. Raw HVSR data for each HVSR measurement are presented in the attached. The HVSR data-collection sites are designated by a county sequential numbering system (LVHVSR1, LVHVSR2, etc. where LV indicates Livingston County). Additional HVSR measurements at a HVSR data-collection site are indicated by a sequential number extension (LVHVSR27.01, LVHVSR27.02, etc.). 1 Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. References Brown, C.J., Voytek, E.B., Lane, J.W., Jr., and Stone, J.R., 2013, Mapping bedrock surface contours using the horizontal-to-vertical spectral ratio (HVSR) method near the middle quarter area, Woodbury, Connecticut: U.S. Geological Survey Open-File Report 2013-1028, 4 p., available at http://pubs.usgs.gov/of/2013/1028. Chandler, V. W., and Lively, R. S., 2014, Evaluation of the horizontal-to-vertical spectral ratio (HVSR) passive seismic method for estimating the thickness of Quaternary deposits in Minnesota and adjacent parts of Wisconsin: Minnesota Geological Survey Open File Report 14-01, 52 p., https://conservancy.umn.edu/handle/11299/162792. Johnson, C. D. and Lane, J. W., 2016, Statistical comparison of methods for estimating sediment thickness from horizontal-to-vertical spectral ratio (HVSR) seismic methods: An example from Tylerville, Connecticut, USA, in Symposium on the Application of Geophysics to Engineering and Environmental Problems Proceedings: Denver, Colorado, Environmental and Engineering Geophysical Society, pp. 317-323, https://doi.org/10.4133/SAGEEP.29-057. Lane, J.W., Jr., White, E.A., Steele, G.V., and Cannia, J.C., 2008, Estimation of bedrock depth using the horizontal-to-vertical (H/V) ambient-noise seismic method, in Symposium on the Application of Geophysics to Engineering and Environmental Problems Proceedings: Denver, Colorado, Environmental and Engineering Geophysical Society, pp. 490-502, https://doi.org/10.4133/1.2963289.