Kupaianaha: 1986-1989
In July 1986, just as it appeared that Puu Oo would start the 48th
episode, magma began to erupt from new fissures at the base of the cone
(Heliker and Wright, 1991). Another fissure opened 2 miles (3 km) down
rift to form the Kupaianaha vent. Episode 48, sometimes called the
Kupaianaha eruption, was to become the longest of all the eruptive
episodes to date.
A Change in Eruptive Style
With the change to the new vent, the style of eruption also
changed. Unlike the discontinuous, high-fountaining eruptions of Puu Oo,
Kupaianaha erupted continuously with gentle effusion of lava. A lava
pond developed over the Kupaianaha vent. Repeated overflows of the lava
pond built a 180-foot (55 m) tall
shield
in less than a year (Heliker and Wright, 1991). In this photo, the
surface of the pond is covered by a thin crust of solidified lava. The
Puu Oo cone is in the background. Photograph by J.D. Griggs, U.S.
Geological Survey, January 13, 1987.
The cause of the change in eruptive style is a topic of continuing
research. Prior to the eruption, a reservoir of magma existed in the
east rift zone beneath the present location of the Puu Oo vent. This
local reservoir may have played a role in triggering or sustaining
fountaining episodes. No magma was stored in the rift zone below the
site of the Kupaianaha eruption. The magma that arrived at Kupaianaha
contained less gas because most of the gas escaped as the magma passed
beneath Puu Oo. Gas is need to generate fountaining eruptions. Although
volcanologists have numerous monitoring techniques, it can still be
difficult to determine exactly what controls the behavior of a
volcano.
Lava Meets the Ocean
The Kupaianaha lava pond (just to the right of center on the
skyline) provided a steady supply of lava to flows advancing toward the
ocean. Lava flows crusted over or inflated to produce
lava tubes.
Lava tubes insulate the lava; thus, they remain fluid and
can travel great distances (6.9 miles; 11 km in this photo) from the vent
to the coast. The upper tube system is marked by a series of steaming
areas. By late 1986, lava tubes reached the ocean near the small
community of Kapaahu. Eleven homes were destroyed. In early 1987, lava
flows traveled farther to the east and destroyed 14 homes in the Kalapana
Gardens subdivision. In this photo, the Puu Oo cone is on the skyline to
the left of center. Kupaianaha is the shield on the horizon near the
right margin of the photo. Aa from the Puu Oo eruptions flowed down
Pulama
Pali.
Some flows buried portions of the
Royal Gardens subdivision. Note the roads and houses.
Pahoehoe
lava of the Kamoamoa flow field is on the left and bottom of the
photograph. Photograph by J.D. Griggs, U.S. Geological Survey, December
28, 1987.
The upper part of the tube system is marked by a series of steaming
areas. Kupaianaha is at the bottom of the photo. The steam plume
produced by lava pouring from the tube into the ocean is in the top right
corner. The distance from the vent to the ocean is about 6 miles (10
km). Photograph by J.D. Griggs, U.S. Geological Survey, April 21,
1988.
Thermal infrared map of the Kupaianaha flow field. The underground
storage and transport of lava in the tube system is shown in yellow from
the top to the bottom of the slide. The bright colored area at the
bottom of the slide is the plume of hot water produced by lava entering
the ocean. Photo by V.J. Realmuto, Jet Propulsion Laboratory, California
Institute of Technology, October 1, 1988.
Lava continued to pour into the ocean from mid-1987 through 1989.
During this period, several major lava tubes developed and broke down.
New lava tubes and breakouts from developed lava tubes increased the size
of the lava flow field. The interaction of lava and water generated an
acidic steam plume, black sand, and, with the proper conditions, littoral
cones. Photograph by T.J. Takahashi, U.S. Geological Survey, February
10, 1988.
Wahaula heiau was constructed in the 13th century during a change to more
strict worshipping rituals. Wahaula was the first luakini heiau and
remained in use until 1819. In 1938, the Kalapana Extension Lands were
added to Hawaii National Park. In 1965, the National Park built the
Wahaula Visitor Center to interpret the cultural features of the coastal
area. Photograph courtesy of National Park Service, October 1967.
By June 1989, lava destroyed Wahaula Visitor Center. Photograph by J.D.
Griggs, U.S. Geological Survey, June 22, 1989.
Subsequent flows surrounded Wahaula heiau (bottom center). Several homes
in Hawaii Volcanoes National Park and the Royal Gardens subdivision were
also overrun by lava. Photograph by C. Heliker, U.S. Geological Survey,
May 11, 1994.
