Figure GPS velocity vectors and
uncertainties (red) in the area of the CGM [Zeng and Shen,
2016; Herring
et al., 2016; McCaffrey et al.,
2013; Crowell et al.,
2013]. The 1339 vectors are references to the
Stable North America Reference Frame (SNARF). The blue
vectors are from a model (0.01˚ grid spacing) using a
vector gridding method called gpsgridder [Sandwell and
Wessel, 2016].