Geologic Background:
Kilauea is one of five coalescing volcanoes that
comprise the island of Hawaii. Historically its eruptions
originate primarily from the summit caldera or along one
of the lengthy E and SW rift zones that extend from the
caldera to the sea. The latest Kilauea eruption began in
January 1983 along the east rift zone. The eruption's
early phases, or episodes, occurred along a portion of
the rift zone that extends from Napau Crater on the
uprift (towards the summit) end to ~8 km E on the
downrift end (towards the sea). Activity eventually
centered on the area and crater that was later named Pu`u
`O`o.
Historic Activity:
- Written records of Kilauea's activity began in
1823.
Recent Activity:
- The current activity at Kilauea is along the East
Rift Zone of Kilauea and began on January 3, 1983 at a
vent named Pu'u O'o. During the period from January 1983
to July 1986 there were 47 eruptions along a 2 mile
segment of the rift zone. These eruptions typically
lasted less than 2 days, built spatter and cinder cones,
and fed lava flows up to 8 miles long. Flows entered the
Royal Gardens subdivision on four occasions during this
period and destroyed many homes.
- Phase 48 began in July 1986, when activity shifted 3
kilometers down the rift zone. A lava shield has been
built with a lava pond near the summit feeding flows
through a lava tube system. Activity here has been has
continuous since July 1986. The estimated eruption rate
of about a 500,000 cubic meters per day has continue
since phase 48 began. Flows first reached the sea below
Royal Gardens on November 28, 1986, 12 km from the vent.
Fountaining activity resumed at Pu'u O'o in January 1988.
and has continued into March 1988. Flows fed by tubes
continued to enter ocean in February 1990. Flows entered
Kalapana Gardens subdivision in April 1990 and later
reached the coast. Flows again reached ocean on Royal
Gardens side in October. Flows continued to entered the
ocean on both the Kalapana and Royal Garden sides through
February 1991. Lava continued to enter the ocean at
several points from April 1991 to early September when
numerous breakouts from tube system began feeding surface
flows and cut off supply of lava to coast.
- Episode 49 began when new fissure vents opened on
Nov. 8, 1991, between the east rift's two active vents
(Kupaianaha and Pu'u O'o) feeding aa flows that advanced
into the remnants of Royal Gardens subdivision. Lava
production from the East rift zone's Kupaianaha vent
declined steadily through January 1992 and ended in early
February. Renewed activity in Pu'u O'o was first observed
on December 4, 1991 and the small lava lake at Pu'u O'o
remained active through July 1992.
- Episode 50 began on February 17, 1992 from a new
fissure on the west flank of Pu'u O'o and continued till
March 5.
- On March 7 Episode 51 began and was continued through
August with nine pauses, each lasting less than a week.
Activity from the Episode 51 vents continued
intermittently during September.
- Following a M 4.5 earthquake on Oct. 2, 1992, new
vents (Episode 52) opened on the south flank of Pu'u O'o.
Activity from these vents (4 spatter cones) was vigorous
till Oct. 7 and continued very sluggishly till October 16
and produced a 3-km long flow.
- Activity at the Episode 51 vents which had paused
from Sept. 27 till Oct. 3, then vigorous activity resumed
and lava continued to flow down the shield to the SE and
SW. The flows crossed the Holei Pali on Nov. 3, the Chain
of Craters Road on Nov. 7 and entered the ocean on Nov. 8
at bay at Kamaoamoa. By early December, lava had built a
1.1 km-wide delta extending 300 m into Kamoamoa Bay from
the former shoreline. Almost all of the lava erupted from
the vent in early December reached the ocean through the
lava-tube system. The magma supply to Episode 51 vents
was interrupted on Feb. 8, 1993 and the lava tube system
drain and flows stagnated by Feb. 9.
- The first 10 years of the eruption produced roughly
1.4 cu. km. of lava. The flow field covered more than 83
sq. km. and about 150 hectares of new land had been added
at the coast. Lava flows had destroyed 181 homes in
several south-flank communities.
- Episode 53 activity began on Feb. 16, 1993, when the
crater of Pu'u 'O'o began to refill and lava entered the
episode 51 tube system. Lava continued to reach the ocean
at the Kamoamoa delta in 1995.
- Activity has continued through 2001 with branching
lava flows and ocean entries.
Data Sources:
- Smithsonian's SEAN Bulletin (V. 8 to 14)
- Global Volcanism Network (V. 15 to V. 26).
|