Long-term eruptive activity at a submarine arc volcano.
Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes.
Embley
Robert W
RW
NOAA/PMEL, 2115 SE O.S.U. Drive, Newport, Oregon 97365-5258, USA. robert.w.embley@noaa.gov
Chadwick
William W
WW
Baker
Edward T
ET
Butterfield
David A
DA
Resing
Joseph A
JA
de Ronde
Cornel E J
CE
Tunnicliffe
Verena
V
Lupton
John E
JE
Juniper
S Kim
SK
Rubin
Kenna H
KH
Stern
Robert J
RJ
Lebon
Geoffrey T
GT
Nakamura
Ko-ichi
K
Merle
Susan G
SG
Hein
James R
JR
Wiens
Douglas A
DA
Tamura
Yoshihiko
Y
D000818:Animals; D017753:Ecosystem; D005843:Geography; D055593:Geological Phenomena; D005844:Geology; D009792:Oceans and Seas; D013997:Time Factors; D018707:Volcanic Eruptions / Q000706:statistics & numerical data*