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The last ash explosion was reported on March 10, 1955, but red-hot lava remained in the crater until June 1955.4647 After the 1954–1955 eruption, Ngauruhoe steamed semi-continuously, with numerous small eruptions of ash derived from comminuted vent debris.Incandescent ejecta were seen in January 1973, and ash erupted in December 1973 contained juvenile glassy andesite shards.53 Cannon-like, highly explosive eruptions in January and March 1974, the largest since 1954–1955, threw out large quantities of ash and incandescent blocks, one of which was reported as weighing 3000 tonnes and thrown 100 m.5461 Ash and blocks up to 30 m across were ejected and scattered within a radius of 3 km from the summit.All flows were of aa lava (as was the February 1949 flow), typified by rough, jagged, clinkery surfaces made up of blocks of congealed lava.

503–525 (1998), and is reproduced here with the permission of the Creation Science Fellowship of Pittsburgh ( Ngauruhoe is an andesite stratovolcano of 2291 m elevation, rising above the Tongariro volcanic massif within the Tongariro Volcanic Center of the Taupo Volcanic Zone, North Island, New Zealand (fig.1).12 Though not as well publicized as its neighbor, Mt.1) and is up to 50 km wide in the central part, narrowing northward and southward. Ngauruhoe in the Taupo Volcanic Zone (TVZ), New Zealand, showing the main structural features.This volcanotectonic depression (Taupo-Rotorua depression6) comprises four rhyolitic centers (Rotorua, Okataina, Maroa, and Taupo), plus the calc-alkaline Tongariro Volcanic Center, part of a young ( Fig. The shaded area is the andesite arc, and the inset shows the major components of the boundary between the Australian and Pacific Plates in the New Zealand region (arrows indicate relative motions).Ruapehu (about 12 km to the south), Ngauruhoe is an imposing, almost perfect cone that rises more than 1000 m above the surrounding landscape.

Eruptions from a central 400 m diameter crater have constructed the steep (33°) outer slopes of the cone.34 The Taupo Volcanic Zone, a volcanic arc and marginal basin of the Taupo-Hikurangi arc-trench (subduction) system,5 is a southward extension on the Tonga-Kermadec arc into the continental crustal environment of New Zealand’s North Island. Ngauruhoe in the Taupo Volcanic Zone, produced andesite flows in 19 and avalanche deposits in 1975.Potassium-argon “dating” of five of these flows and deposits yielded K-Ar model “ages” from Ar* content.It has been interpreted as oblique subduction of the Pacific plate beneath the Australian plate.The zone extends approximately 300 km north-northeast across the North Island from Ohakune to White Island (fig.By February 12 the flow had ceased moving, subsequent mapping placing its volume at about 575,000 m34 Further explosive pyroclastic (ash) eruptions followed, reaching a maximum about February 19-21 . The eruption from May 13, 1954, to March 10, 1955, began with explosive ejection of ash and blocks, although red-hot lava had been seen in the crater five months previous.35 Fig.