The
pressure sensor instrument is placed on ROPOS. The instrument is lifted
by ROPOS onto a triangular-shaped platform at each benchmark site.
There are 36 hours of dive time planned for R855, almost all of it devoted
to taking pressure sensor measurements. Five locations (Caldera center,
Magnesia, Marker 33, Bag City and South Pillow Mound) within the caldera
have benchmark platforms where 30 minute measurements are performed. The
measurements are designed to see if Axial volcano is inflating, due to
magma accumulation underground. The measurements from previous years show
that the center of the caldera has been uplifting at a rate of 20 cm/yr
since 2000. Dive R855 began at 8am PDT and continues through the night.
