Geologic Background:
The uninhabited 2 x 2.4 km White Island, 50 km
NNE of Whakatane (North Island), is the emergent summit
of a 16 x 18 km submarine complex that consists of two
overlapping stratovolcanoes. Many points on the SE crater
wall lie below sea level, giving the appearance that the
main crater is open in that direction. Intermittent steam
and tephra eruptions have occurred throughout the short
historical period, but White Island activity also forms a
prominent part of Maori legends.
Historic Activity:
- About 30 small to moderate explosive eruptions have
occurred between 1826 and 1980.
Recent Activity:
- Jan. 1984, tephra eruption.
- Feb. 1986, minor magmatic eruption with associated
tephra fall. May to Aug. 1986, intermittent
phreatomagmatic activity and associated tephra
falls.
- On Jan. 25, 1987 the largest explosion in 10 years
occured. Ballisticly projected blocks 3 feet in diameter
were abundant at 1500 feet from vent. Intermittent small
explosions and steam and ash eruptions continued through
October 1990 producing explosions, tephra, and a new
craters.
- Tephra eruption on Feb. 8, 1991. Light tephra fall on
March 20, 1991. New collapse pit in April 1991. New vent
formed in May 1991, with continued explosions into Oct.
1991. Another new vent formed in October 1991 and tephra
emission was continuing through January 1992. Major
explosions occurred on January 17, 1992 from the new Wade
Crater vent and resulted in a change from Strombolian
ejections of scoriaceous bombs and juvenile ash to
emissions of ash-sized tephra dominated by lithics and
altered glass. Continuing vigorous explosive activity
from Wade Crater into April. A new collapse crater (named
Princess) developed in mid-April. Voluminous clouds of
steam and ash were observed emerging from three craters
in mid-May. Wade Crater was enlarge by a block eruption
prior to June 28, 1992. Continuing activity (ash and
block eruptions), January to May 1993. Phreatic eruptions
on Oct. 19 lasted for about 45 minutes and resulted in a
very pale gray ash plume which rose about 1 km above the
summit of Mt. Gisborne.
- Small ash eruptions in January and February 1994. No
additional activity thru June 1994. A small eruption from
Wade Crater on July 28 ejected mud and ballistic blocks.
No eruptions for rest of year.
- A small ash eruption from an active vent within Wade
Crater occurred around June 29-30, 1995. Slow uplift of
main crater floor through March 1996.
- Minor gas-and-ash eruptions in August and October
1998. A new vent named PeeJay formed in August 1998.
- A new vent named Metra formed on the floor of the
main 1978/90 crater in January 1999. Activity continued
through end of year.
- Ash emissions resumed in March 2000. Largest eruption
in 20 years occurred on July 27 and formed a new crater.
Continued ash emission through mid-June 2001.
Data Sources:
- Smithsonian's SEAN Bulletin (V. 8, No. 3 to V. 14,
No. 12)
- Global Volcanism Network (V.15, No. 3 to V. 26, No.
9).
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