First sighting responsible for undersea eruption
New Zealand scientists are investigating active undersea volcanos, north of New Zealand. New images reveal the impacts of a significant eruption on the seafloor.
NIWA research vessel Tangaroa has just mapped the Kermadec volcano that erupted 800 kilometres north east of Tauranga, on 19 July 2012, producing a pumice raft the size of Canterbury.
Tangaroa recently embarked on a 23-day voyage of discovery in the Kermadecs, north of New Zealand, to study the volcanic chain that stretches for 1000 kilometres north from Bay of Plenty.
"When we mapped the area yesterday", says NIWA ocean geology scientist Dr Joshu Mountjoy, "we found a new volcanic cone which has formed on the edge of the volcano, towering 240 metres above the crater rim.
"It is fantastic to be able to record the change on the seafloor following these kinds of events."
The Havre volcano eruption was strong enough to breach the ocean surface from a depth of 1100 metres. It produced clouds of ash visible by satellite, and a pumice raft that covered an area of 22,000 square kilometres.
The voyage, led by NIWA's volcanologist Dr Richard Wysoczanski, comprises geology and biology scientists from NIWA, GNS Science, as well as students from Victoria University of Wellington and The University of Auckland.
Dr Wysoczanski says, "One of the most exciting aspects of the cruise is the chance to map Havre volcano which, we have now confirmed, erupted in July. We know the shape of the volcano from previous research. Using the multibeam echosounder, we made a before and after comparison of the volcano to determine the size of the eruption and the change it has made to the seafloor."
NIWA had previously mapped Havre volcano in 2002, showing a 1 kilometre high undersea mountain with a 5 kilometre wide, 800 metre deep central crater. This central steep-walled crater is a caldera, which is a type of volcano, like Lake Taupo, known to produce large and violent eruptions.
