[en] The effects of long-wavelength (>100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (ΔrM) have root-mean-square (RMS) values for 1994–1998 as large as 8 mm, with ranges up to 30 mm, and are predominantly annual in character. Regional strains are on the order of 20 nanostrain for tilt and 5 nanostrain for horizontal deformation. We compare ΔrM with observed Global Positioning System (GPS) heights (ΔrO) (which include adjustments to remove estimated effects of atmospheric pressure and annual tidal and non-tidal ocean loading) for 147 globally distributed sites. When the ΔrO time series are adjusted by ΔrM, their variances are reduced, on average, by an amount equal to the variance of the ΔrM. Of the ΔrO time series exhibiting a strong annual signal, more than half are found to have an annual harmonic that is in phase and of comparable amplitude with the annual harmonic in the ΔrM. The ΔrM time series exhibit long-period variations that could be mistaken for secular tectonic trends or postglacial rebound when observed over a time span of a few years.
Disciplines :
Earth sciences & physical geography Physics
Identifiers :
UNILU:UL-ARTICLE-2008-950
Author, co-author :
VAN DAM, Tonie ; Luxembourg National Museum of National History and the European Center for Geodynamics and Seismology
Wahr, J.; Department of Physics and CIRES, University of Colorado, USA
Milly, P. C. D.; U.S. Geological Survey, Princeton, New Jersey + Geophysical Fluid Dynamics Laboratory/NOAA, Princeton, New Jersey
Shmakin, A. B.; Geophysical Fluid Dynamics Laboratory/NOAA, Princeton, New Jersey
Blewitt, Geoffrey; Nevada Bureau of Mines and Geology, Reno, Nevada + Seismological Laboratory, University of Nevada, Reno
Lavallee, D.; Department of Geomatics, University of Newcastle uponTyne, England
Larson, K.; Department of Aerospace Engineering, University of Colorado, Boulder, Colorado
Language :
English
Title :
Crustal displacements due to continental water loading
