Garry Massoth (personal communication). About 87 % of the volcanoes are
located in the Tonga-Kermadec Ridge (de Ronde et al. 2003). Several times a year,
it is common for the population of the volcanic islands to feel large seismic
quakes. Some historical eruptions along the Tonga-Kermadec Ridge were reported
from Raoul Island in 1800, and from the Monawai volcano in 1998.
The first submarine eruption observed by scientists was on May 5, 2009 in the
northern area of the Tonga-Kermadec ridge near the island of Tonga, to the west of
the Mata volcano. Scientists on aboard the R.V. Thompson using an ROV witnessed two active volcanic eruptions during two of Jason’s ROV dives at depths of
1174 and 1208 m. A report written by David A. Clague, senior scientist from the
Monterey Aquarium Research Institute in California, described the events and was
published on the Web (see Chap. 5).
Cooperative Programs and Sea-Going Expeditions
It was after the discovery of hydrothermalism and the recovery of the first sulfide
samples dredged from the calderas of the Brothers and Rumble II volcanoes from
the southern Kermadec arc (de Ronde et al. 2005), that an international cooperative program organized by New-Zealand and Germany took place. This program
was headed by professor Peter Stoffers from the University of Kiel and by Ian
Wright from the National Institute of Water and Atmospheric Research in Wellington, New Zealand. The program was designed to study several volcanic edifices along the arc.
The first F.S. SONNE cruise (Leg 135) took place in September 1998 and
discovered black-smoker venting as well as low-temperature, diffuse venting
within the Brothers seamount caldera, on the Monowai, Rumble III and Clark
volcanoes (Stoffers et al. 1999a, b) located along the Tonga-Kermadec ridge
(Fig. 10.2). The Brothers seamount was observed in detail with a deep-towed
bottom video camera system (OFOS = Ocean floor Observation System) and a
geological map was compiled. This seamount revealed the presence of an extensive hydrothermal sulphide field covering of more than 200 m in diameter that was
concentrated on the southern rim of the caldera. The success of this cruise gave an
incentive to the international community, mostly the US, Japan and New Zealand,
to take the lead in pursuing research for mineral deposits in the area. Between1999
until 2005, sea-going expeditions surveyed more than 6 new volcanoes along the
Tonga-Kermadec Ridge system (De Ronde et al. 2005).
The second F.S. SONNE cruise (Leg 167) took place between October 12 and
December 2, 2002, to carry out additional bathymetric surveys and to sample rocks
from the Tonga-Kermadec volcanic chain. As mentioned before, it is believed that
buoyancy in the deep-seated mantle of the Earth creates an ideal situation where
two colliding plates could form a deep trench and then subsequent lithospheric
uplift could form a volcanic ridge, where volcanic islands would eventually be
Volcanoes of the Tonga-Kermadec Ridge
353
located in the Tonga-Kermadec Ridge (de Ronde et al. 2003). Several times a year,
it is common for the population of the volcanic islands to feel large seismic
quakes. Some historical eruptions along the Tonga-Kermadec Ridge were reported
from Raoul Island in 1800, and from the Monawai volcano in 1998.
The first submarine eruption observed by scientists was on May 5, 2009 in the
northern area of the Tonga-Kermadec ridge near the island of Tonga, to the west of
the Mata volcano. Scientists on aboard the R.V. Thompson using an ROV witnessed two active volcanic eruptions during two of Jason’s ROV dives at depths of
1174 and 1208 m. A report written by David A. Clague, senior scientist from the
Monterey Aquarium Research Institute in California, described the events and was
published on the Web (see Chap. 5).
Cooperative Programs and Sea-Going Expeditions
It was after the discovery of hydrothermalism and the recovery of the first sulfide
samples dredged from the calderas of the Brothers and Rumble II volcanoes from
the southern Kermadec arc (de Ronde et al. 2005), that an international cooperative program organized by New-Zealand and Germany took place. This program
was headed by professor Peter Stoffers from the University of Kiel and by Ian
Wright from the National Institute of Water and Atmospheric Research in Wellington, New Zealand. The program was designed to study several volcanic edifices along the arc.
The first F.S. SONNE cruise (Leg 135) took place in September 1998 and
discovered black-smoker venting as well as low-temperature, diffuse venting
within the Brothers seamount caldera, on the Monowai, Rumble III and Clark
volcanoes (Stoffers et al. 1999a, b) located along the Tonga-Kermadec ridge
(Fig. 10.2). The Brothers seamount was observed in detail with a deep-towed
bottom video camera system (OFOS = Ocean floor Observation System) and a
geological map was compiled. This seamount revealed the presence of an extensive hydrothermal sulphide field covering of more than 200 m in diameter that was
concentrated on the southern rim of the caldera. The success of this cruise gave an
incentive to the international community, mostly the US, Japan and New Zealand,
to take the lead in pursuing research for mineral deposits in the area. Between1999
until 2005, sea-going expeditions surveyed more than 6 new volcanoes along the
Tonga-Kermadec Ridge system (De Ronde et al. 2005).
The second F.S. SONNE cruise (Leg 167) took place between October 12 and
December 2, 2002, to carry out additional bathymetric surveys and to sample rocks
from the Tonga-Kermadec volcanic chain. As mentioned before, it is believed that
buoyancy in the deep-seated mantle of the Earth creates an ideal situation where
two colliding plates could form a deep trench and then subsequent lithospheric
uplift could form a volcanic ridge, where volcanic islands would eventually be
Volcanoes of the Tonga-Kermadec Ridge
353