Most of the time bulbous mantle plumes do not create a GPS noticeable uplift. Hence why they as to date have little physical evidence of their existence.
However I am sure the area is monitored just because of the areas history.
86 posted on 09/05/2012 1:29:46 PM PDT by winoneforthegipper
("If you can't ride two horses at once, you probably shouldn't be in the circus" - SP)