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TitlePresent-day tilting of the Great Lakes region based on water level gauges
AuthorMainville, A; Craymer, M RORCID logo
SourceGeological Society of America Bulletin vol. 117, no. 7-8, 2005 p. 1070-1080,
Alt SeriesEarth Sciences Sector, Contribution Series 2005661
PublisherGeological Society of America
Mediapaper; on-line; digital
File formatpdf
NTS30; 31C; 31D; 31E; 40; 41; 42C; 42D; 52A
AreaGreat Lakes; Lake St. Clair; Canada; United States of America
Lat/Long WENS -93.0000 -75.0000 49.0000 41.0000
Subjectstectonics; regional geology; hydrogeology; lakes; water levels; crustal movements; crustal tilt; postglacial evolution; models; isostasy; isostatic rebound; trend surface analyses; resource management; surface waters; statistical methods; satellite geodesy; hydrologic budget; bathymetry; navigation systems
Illustrationssketch maps; tables; time series
ProgramCanadian Geodetic Service
AbstractBy using monthly mean water levels at 55 sites around the Great Lakes, a regional model of vertical crustal motion was computed for the region. In comparison with previous similar studies over the Great Lakes, 15 additional gauge sites, data from all seasons instead of the 4 summer months, and 8 additional years of data were used. All monthly water levels available between 1860 and 2000, as published by the U.S. National Ocean Survey and the Canadian Hydrographic Service, were used. For each lake basin, the vertical velocities of the gauge sites relative to each other were simultaneously computed, using the least-squares adjustment technique. Our algorithm solves for and removes a monthly bias common to all sites, as well as site-specific biases. It also properly weighs the input water levels, resulting in a realistic estimation of the uncertainties in tilting parameters. The relative velocities obtained for each lake were then combined to obtain relative velocities over the entire Great Lakes region. Finally, the gradient of the relative rates for the regional model was found to agree best with the ICE-3G global isostatic model of Tushingham and Peltier, whereas the ICE-4G gradients were too small around the Great Lakes.

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