Check of gravity/elevation change correlation
The above plot shows gravity change as a function of elevation change for all stations in the February, April, and May campaigns which have both gravity and GPS data. March is omitted, as it is the baseline GPS campaign for these elevation changes. The green line is the theoretical curve: -3.086 uGal/cm [free-air gravity gradient]. The black-background image is linked to a B&W Postscript image for printing. Note the extremely poor correlation between the data and the theoretical curve; this indicates gravity changes are due to sources other than subsidence.