What is the evidence that the lava dome is no longer growing?
All of the indicators of dome growth have gradually declined to pre-eruption levels, where they have remained since late January 2008. These indicators include seismicity, ground deformation, and volcanic gas emissions. The most direct evidence is that, since late January, repeat photographs from cameras on the crater rim and floor show little or no change in the shape of the new dome, except for a small amount of sagging that would be expected even if lava extrusion has stopped. That observation was confirmed recently by placing a GPS spider on the part of the new dome that had been growing for the past year. Data from the spider indicate that it has moved downwards and away from the center of the dome by less than an inch per day since February 15, motion that is consistent with gravitational settling of the dome and strong evidence that dome growth has stopped or slowed dramatically.
