The New Zealand American Submarine Ring of Fire 2005 Expedition
Bob Embley
Co-Chief Scientist for the New Zealand American Submarine Ring of Fire Expedition
(Legs 1 and 2)
Geophysicist
NOAA Vents Program, Pacific Marine Environmental Laboratory Newport,
Oregon
Gary Massoth
Co-Chief Scientist for the New Zealand American Submarine Ring of Fire Expedition
(Leg 1)
Principle Scientist
Institute of Geological and Nuclear Sciences Ltd
Lower Hutt, New Zealand
Alex Malahoff
Co-Chief Scientist for the New Zealand American Submarine Ring of Fire Expedition
(Leg 2)
Chief Scientist, Chief Executive, Institute of Geological and Nuclear Sciences
Ltd
Lower Hutt, New Zealand
The New Zealand American Submarine Ring of Fire 2005 (NZASRoF'05)
expedition on the University of Hawaii research vessel Ka'imikai-o-Kanaloa will
begin April 3 in Pago Pago, American Samoa and end in Tauranga, New Zealand
on May 10. An international team of explorers from New Zealand and the
United States will conduct dives at approximately six volcanoes using the
human-occupied vehicles (submersibles) PISCES IV and V, operated by the
Hawaii Undersea Research Laboratory (HURL). The submersibles will be used
to explore the geology, biology and chemistry of submarine volcanoes along
the largely unexplored Kermadec Arc that extends N-NE of New Zealand's
North Island. These volcanoes and the adjacent Kermadec Ridge lie westward
of the 800 mile-long Kermadec Trench, where the western edge of the vast
Pacific plate descends beneath the Australasian plate to the west. The
volcanoes form as gases and water rising off the down-going plate induce
melting of the surrounding rocks forming magma lenses beneath the volcanoes.
This expedition is the culmination of seafloor mapping and oceanographic
surveys conducted jointly by New Zealand and U.S. scientists over the past
5 years. Two New Zealand Crown Research Institutes (Geological and Nuclear
Sciences, or GNS, and National Institute of Water and Atmospheric Research,
or NIWA), and the NOAA Ocean Exploration Program have joined together to
provide the funding and the scientific expertise to make this expedition
possible. Sixteen scientists representing the disciplines of geology, chemistry
and biology will take part in the explorations.
Expedition is a Culmination of 5 Years of Preparation
Although most of the target volcanoes will be visited for the first time with
a submersible, we will be relying on maps and other ocean surveys conducted
over the past 5 years by New Zealand and U.S. scientists, many of whom are
taking part in this expedition. Many of these volcanoes were unknown before
new oceanographic and bathymetric surveys were conducted by the GNS ,
the NIWA ,
and the Pacific Marine Environmental Laboratory NOAA Vents Program in 1999-2004. Three
joint expeditions have been made on the New Zealand research vessel Tangaroa
since 1999, known as NZAPLUME (New Zealand American PLUme Mapping Expedition) I, II and III , that focused
on locating the active vent sites by mapping and sampling hydrothermal plumes
associated with active venting.
Deciding on the Dive Sites
How active are these submarine volcanoes? Several of the
volcanoes have had historic activity detected by hydrophones and/or direct
observations from ships or planes (e.g., Monowai, Rumble V) over the past
30 years. For most, however, the potential for activity is uncertain because
submarine eruptions are difficult to monitor. However, one measure of a
volcano's potential for eruption is the presence or absence of an underlying
heat source. Heat sources beneath volcanoes above sea level usually give
rise to hot springs and fumaroles on the surface. This is also the case
for submarine volcanoes. A seafloor hot spring can actually be much hotter'
than one at sea level because of the higher pressures. Water boils at
almost 250° C (~480°F) at only 350 meters (1165 ft.) depth. These
seafloor hot springs can produce buoyant plumes of chemically anomalous
water that are detectable with conventional oceanographic equipment and
techniques. Hundreds of such measurements with a CTD made
along the Kermadec and Tonga submarine volcanoes in the past 5 years
have detected more than 30 hot spring sites. Because some of these sites
are shallower than 100 meters (328 ft.) they reside within the photic
zone. These zones are very unusual because they represent a coincidence
of photosynthetic and chemosynthetic organisms. The implication of this
is not presently known - It is a new area of research.
Two Parts of the Expedition (Legs1 and 2)
The New Zealand American Submarine Ring of Fire Expedition will be divided into two parts. The first Leg will depart from Pago Pago, American Samoa on April 3 and arrive in Tauranga, New Zealand on April 22. After departing Pago Pago and transiting for several days the RV Ka'imikai-o-Kanaloa will arrive at Monowai Volcano. For each volcano visited, the first dive(s) will attempt to locate the source of the most active hydrothermal signals measured on prior cruises. After the sites are located, the dives will concentrate on sampling and more detailed observations, as well as mapping of the sites. Some volcanoes have more than one active site, requiring additional dives. The remotely operated vehicle (RCV-150) will be used in the evening hours after the PISCES returns onboard to locate and map other potential dive sites for the PISCES. In addition, the GNS MINTS plume profiling system will be onboard for site reconnaissance. Dives are also planned at two other sites, Macaulay and W volcanoes during the first leg. After changing some personnel in Tauranga, the second leg of the expedition will conduct dives on several more volcanoes near New Zealand. In addition, 7 moored instrument packages deployed at Brothers Volcano during a joint cruise on the Tangaroa in September, 2004 will be recovered.. These instruments are part of a novel Fluid Flux Experiment designed to assess the amounts of fluids and gases going into the ocean from a submarine volcano.
The scientists involved in this expedition are very excited to be part of one of the first submersible expeditions to these Kermadec submarine volcanoes.