Geologic Background:
Ngauruhoe is the most recent of more than a
dozen composite cones that comprise the large Tongariro
volcanic massif north of Ruapehu. It has grown to be the
highest peak of the massif since its inception about
2,500 years ago.
Tongariro is a large andesitic volcanic massif,
located immediately NE of Ruapehu volcano, that is
comprised of more than a dozen composite cones. Vents
along a NE-trending zone at Red Crater, Blue Lake, North
Crater, and near present-day Ngauruhoe were active at the
beginning of the Holocene. The North Crater
stratovolcano, one of the largest features of the massif,
is truncated by a broad, shallow crater filled by a
solidified lava lake that is cut on the NW side by a
small explosion crater. The youngest cone of the complex,
Ngauruhoe, has grown to become the highest peak of the
massif since its birth about 2500 years ago. The
symmetrical, steep-sided Ngauruhoe, along with its
neighbor Ruapehu to the south, have been New Zealand's
most active volcanoes during historical time.
Historic Activity:
- Ngauruhoe last erupted in February 1975, producing
10-km plumes and pyroclastic flows.
Recent Activity:
- Several seismic swarms were recorded in 1983, along
with actitive fumaroles. No fumaroles were reported in
1995.
Data Sources:
- Smithsonian's SEAN Bulletin (V. 8, No. 5)
- Global Volcanism Network (V.17, No. 5 to V. 20, No.
5).
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