Analysis of GPS Measurements in Eastern Canada Using Principal Component Analysis

Abstract

International audienceContinuous Global Positioning System (CGPS) position time series from eastern North America constrain the pattern and magnitude of regional crustal deformation. Initial analysis delineates consistent uplift patterns, as expected from glacial isostatic adjustment (GIA) predictions, but the associated horizontal deformation is not definitive, in part due to the short time periods for a significant number of the available stations. We employ an eigenpattern decomposition in order to define a unique, finite set of deformation patterns for this continuous GPS data. Similar in nature to the empirical orthogonal functions historically employed in the analysis of atmospheric and oceanographic phenomena, the method derives the eigenvalues and eigenstates from the diagonalization of the correlation matrix using a Karhunen-Loeve expansion (KLE). The KLE technique is used to identify the important modes in both time and space for the CGPS data, modes that potentially include signals such as horizontal and vertical GIA, tectonic strain, and seasonal effects. Here we filter both the vertical and horizontal velocity patterns on different spatiotemporal scales in order to study the potential geophysical sources, after the removal of correlated and random noise. The method is successful in disaggregating the linear vertical signal from more variable and less spatially correlated signals. The vertical and horizontal results are compared to the predictions of the ICE-3G GIA loading model with a number of plausible mantle viscosity profiles. The horizontal velocity analysis allows for qualitative differentiation between several potential GIA models and suggests that, with longer time series, this technique can be employed to remove correlated noise and improve estimates of crustal strain patterns and their sources

Identification of Glacial Isostatic Adjustment in Eastern Canada Using S Transform Filtering of GPS Observations

“…There is a clear indication of a hinge line around 44°N that runs approximately parallel to the Saint Lawrence River in the east (PELTIER, 2002;TUSHINGHAM and PELTIER, 1991), where the lithosphere above the hinge line shows uplift and those portions below the hinge line show subsidence. The vertical velocities obtained by EST filtering are compared in Table 3 with the results obtained by TIAMPO et al (2011), which employs a principal component analysis technique, and are observed to be in close match. A comparison is also made with the velocities obtained by crude fitting of a line to the despiked vertical position time series.…”

“…Between about 7 and 20 ka the ice sheets retreated and GIA began. Current uplift rates are 10 mm/year or more at Hudson Bay and decrease with distance southward (TIAMPO et al, 2011). Present-day GIA models estimate that the hinge line between uplift to the north and subsidence to the south lies near the Saint Lawrence Valley in eastern Canada (VAN DER WAL et al, 2009;KOOHZARE et al, 2006).…”

GPS-based monitoring of surface deformation associated with CO2 injection at an enhanced oil recovery site

“…To account for non-uniformity of CME, Dong et al (2006) developed a spatio-temporal filtering approach based on principal component analysis. This approach has been successfully applied to extract CME in various GPS networks (Savage 1995;Marquez-Azua and DeMets 2004;Tiampo et al, 2004Tiampo et al, , 2012.…”

Investigation of time_changeable seasonal components in the GPS height time series: A case study for Central Europe

“…To test the null hypothesis, whether the first j modes are significant, the F-statistic was computed using (Tiampo et al, 2012):…”