Report on Tongariro (New Zealand) — 1 January-7 January 1920
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 1 January-7 January 1920
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 1920. Report on Tongariro (New Zealand). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 1 January-7 January 1920. Smithsonian Institution and US Geological Survey.
39.157°S, 175.632°E; summit elev. 1978 m
All times are local (unless otherwise noted)
A short-lived (~1-2 minutes) phreatic eruption occurred at the Te Mari craters area, followed by a series of discrete small earthquakes over the next few tens of minutes. An ash plume drifted E and ashfall was reported in areas around the volcano. Blocks of old and hydrothermally altered lava, as large as 1 m in diameter, ejected by the eruption fell 1.5-2 km from the Te Mari craters area. The last eruption occurred in 1896.
Geologic Background. Tongariro is a large volcanic massif, located immediately NE of Ruapehu volcano, that is composed of more than a dozen composite cones constructed over a period of 275,000 years. Vents along a NE-trending zone extending from Saddle Cone (below Ruapehu) to Te Maari crater (including vents at the present-day location of Ngauruhoe) were active during several hundred years around 10,000 years ago, producing the largest known eruptions at the Tongariro complex during the Holocene. North Crater stratovolcano 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, Ngauruhoe, is also the highest peak.