CoAxial Segment had a well-documented dike injection and eruption
episode in June-July of 1993 which was detected and monitored
by the NOAA/Navy SOSUS real-time T-wave
monitoring system. Two "event plumes" were found over the
axial valley centered around 46° 30'N where the T-waves had
concentrated during the latter part of the episode. This site
(which subsequently was known as the Flow site) became the target
for dives with the Canadian remotely operated vehicle ROPOS
off the NOAA R/V DISCOVERER in mid-July, 1993, during which
a fresh, venting lava flow 2.5 km long was discovered, mapped
and sampled. The lava flow was erupted on a ridge just north
of an older volcano cone on the median volcanic ridge. Extensive
venting was also found southward from the cone for about 4 km
within a small graben.
eruption site for more information.
for full-sized image.