GEOSCAN Search Results: Fastlink

GEOSCAN Menu


TitleSeismic evaluation of a multipurpose tower in Yellowknife, Northwest Territories, Canada
AuthorEdwards, W N; Asudeh, I; Andews, C; Jensen, G; Murphy, F; Ashlie, R
SourceSeismological Research Letters vol. 83, no. 5, 2012 p. 787-797, https://doi.org/10.1785/0220120028
Year2012
Alt SeriesEarth Sciences Sector, Contribution Series 20110384
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceNorthwest Territories
NTS85J/07
AreaYellowknife
Lat/Long WENS-115.0000 -114.5000 62.5000 62.2500
Subjectsgeophysics; seismic interpretations; seismicity; seismic data; seismology; seismological network
Illustrationslocation maps; histograms; rose diagrams; plots; tables
ProgramCanadian Hazard Information Service, Canadian Hazard Information Service
Abstract(unpublished)
In 2011, decisions were made to significantly upgrade the Yellowknife seismic array in the Northwest Territory, Canada to modern standards. Part of this upgrade required the installation, at each element of the array, of a 7.62m free-standing aluminum frame tower to provide a platform for solar panels and radio communications antenna. To ensure current seismic background levels at the array would not be adversely affected by vibrations of this tower under wind loading, an experiment was devised to measure the seismic characteristics of the tower on site under actual wind conditions between February 21 and April 4, 2011. Spectral analysis shows that the tower has a fundamental vibrational mode at 2.0 Hz, which decays approximately as R-3, along with a twisting mode and several higher order harmonics within the passband of the short period sensors. Measurement of the modal growth rates as a function of wind speed allows construction of a simple model to determine the minimum safe separation distance between the seismic vault and tower. Based on these findings a separation of between 30 - 40 m is recommended to avoid background contamination with tower-generated noise during the majority of wind conditions likely to be experienced by the array.
GEOSCAN ID290062