Episodes 50, 51, and 52, New Vents on the Flank of the "Old" Puu Oo
Cone: 1992
Eleven days after Kupaianaha shut down, a 490-foot (150 m) long
fissure opened on the uprift (west) flank of the Puu Oo cone, and Episode
50 began. The flows formed a perched lava pond that covered about 0.4
square mile (1 square km). On March 3, 1992, an
intrusion
of magma entered the upper east rift zone of Kilauea, and
Episode 50 stopped abruptly. Photograph by J.D. Griggs, U.S. Geological
Survey, February 18, 1992.
Four days later, Episode 51 started from a fissure on the Puu Oo cone
slightly higher than the Episode 50 fissure. Several new vents formed.
Downslope from the vents, a lava shield, fed by a lava tube, developed
and grew to a height of 200 feet (60 m). The lava shield was capped by a
perched
lava pond.
The eruption at the Episode 51
fissure was punctuated with pauses in activity lasting from hours to
days. In July, the lava pond drained and crusted over. The full volume
of the eruption bypassed the pond and traveled to the south in a lava
tube, reaching the pali (the steep slopes facing the coast) on the March
20, 1992. Lava poised at the edge of the pali and threatened numerous
archaeological features in the park. Fortunately, a pause on July 22
stopped the advance of this flow. The episode restarted and paused
several times from July to October 1992. Photograph of Episode 51 pond
and overflows by T.N. Mattox, U.S. Geological Survey, April 4, 1992.
On October 2, 1992, during a pause in Episode 51, a magnitude-4.5
earthquake occurred on the south flank of Kilauea volcano, not far from
the eruption site. On October 3, Episode 52 started along a fissure on
the south flank of the Puu Oo cone (shown in the above photo). A day
later, activity resumed at the Episode 51 vent. Over the next two weeks,
activity declined at the Episode 52 vent and increased at the Episode 51
vent. Activity was last seen at the Episode 52 vent on October 17. For
the remainder of 1992, the Episode 51 vent remained active. Geologists
at the U.S. Geological Survey's Hawaiian Volcano Observatory suggested
that the October 2 earthquake may have changed the plumbing system near
the eruptive vent. Photograph by C. Heliker, U.S. Geological Survey,
October 3, 1992.
Close-up on the Episode 52 vent, a low lava fountain and adjacent spatter
cone. Note lava channel just left of fountain. South flank of Puu Oo is
on left center margin. Photograph by C. Heliker, U.S. Geological Survey,
October 3, 1992.
Lava Buries Kamoamoa
Kamoamoa was a beautiful green oasis along the mostly barren coast
in the park. In 1986, a black sand beach formed at Kamoamoa. The sand
was pieces of lava that fragmented when it poured from a lava tube into
the ocean. Waves then transported the sand along the coast until it
began to collect in a sheltered area, making the beach. Photograph by
Steve Mattox, January 1989.
Kamoamoa was also an important archeological area that provided insights
into how the Hawaiians lived. This photo is of a Moa heiau. Photograph
by Steve Mattox, November 1992.
This is an aerial view of Kamoamoa.
Chain of Craters Road
slants across the bottom of the photo. A large grassy field and picnic
area is just inland (below) the beach. The short access road leads to
the campground and a trail to the archeological sites. Note the
indentation of the coast where the sand collected to make the beach.
Photograph by Steve Mattox, November 2, 1992.
Lava from the Episode 51 vent reached Paliuli, just above the Chain of
Craters Road, on November 3, 1992. This photo shows lava cascading over
Paliuli on the night of November 3, 1992. Lava crossed the Chain of
Craters Road on November 7. Within a day, lava skirted the eastern side
of the Kamoamoa archaeological area and entered the ocean. The glow on
the horizon marks the location of the vent. Photograph by Steve Mattox.
The flows spread along the black sand beach and began to build a lava
delta out into the bay. This aerial view is to the east. Kamoamoa is
just to the west (left) of the lava delta. The flows at the top of the
photo are from Kupaianaha. Photograph by M. Mangan, U.S. Geological
Survey, November 12, 1992.
Conditions were favorable to allow park visitors close access to lava
flows and the new lava bench. Note visitors are standing on the old sea
cliff, not the new lava bench which was unstable and prone to collapse.
Photograph by Steve Mattox, November 14, 1992.
Large thin flows covered the grassy field at Kamoamoa in only a few
hours. Conditions were safe for visitors to have a close look at lava.
Photograph by Steve Mattox, November 14, 1992.
The flows burned away the bases on the coconut trees, producing tree
molds. Photograph by Steve Mattox, November, 1992.
The presence of lava flows in such a heavily used area of the park
brought new opportunities for interagency cooperation between the staff
of the National Park Service and the U.S. Geological Survey. Photograph
courtesy of U.S. Geological Survey.
By the end of November, the Kamoamoa campground, picnic area, and most of
the archaeological features were buried under lava. Even the black sand
beach, which formed in 1986, was buried. The lava delta continued to
grow.
An unstable lava bench formed at the front of the lava delta. Collapse
and settling of the lava bench produced dramatic steam explosions that
propelled fragments of lava about 300 feet (100m) into the air through a
breach in the lava tube (Mattox and others, 1993). Photo by Steve
Mattox, November 24, 1992.
By late December, 1993, the lava delta extended 980 feet (300 m) beyond
the old shoreline and had added 60 acres (24 hectares) of new land to the
island.
