U.S. Geological Survey - Hawaiian Volcano Observatory

Kilauea - Eruption Summary - Hazards - History

Eruption Continues and New Land Frequently Collapses

This update current as of July 10, 1998. Eruption updates are posted monthly; more frequent updates will accompany drastic changes in activity or increased threat to residential areas.

[Previous eruption updates may be accessed through our archive index.]


Episode 55 of Kilauea's east rift zone eruption continues with very little change in the past several weeks. Lava erupts quietly from vents on the southwest flank of Pu`u `O`o and travels about 12 km through lava tubes to the coast. Between 300,000 and 600,000 m3 of lava enter the ocean every day at two entry points -- Waha`ula and Kamokuna. The Kamokuna entry is the more active one, and the new land built outward from a large littoral cone frequently collapsed into the ocean. A large collapse event on July 6 removed about 3.7 hectares (9.1 acres) of new land.

Thick volcanic fume in the inner crater of Pu`u `O`o often prevents scientists from observing details of the activity there, though they do know that lava continues to rise intermittently from vents in the crater floor. Observers have noted a series of new arcuate cracks around several adjacent pits on the southeast flank of the Pu`u `O`o cone. These cracks suggest this part of the cone is subsiding and may develop into a single large pit (see update of 17 December 1997 for early description of these pits).

Lava Entry Points Remain Hazardous

At the coast, the tube system continues to discharge lava into the ocean at two sites, Waha`ula and Kamokuna. Most of the lava enters the ocean at the Kamokuna entry point, where new land collapses into the ocean without warning. Two significant collapses occurred on June 11 and July 6. See a description of the June collapse, Bench collapse sparks lightning, roiling clouds. These collapses are life endangering; the land itself is destroyed, and numerous explosions ensue as the hot lava reacts violently with the ocean water. For more information about this activity and the associated hazards, see:

Growth and collapse of new land at the Kamokuna entry

May 7 View is southwest across the Kamokuna entry a few days after new land (lava bench) seaward of the littoral cone collapsed into the ocean. The cone is about 10 m tall. Lava pouring into the ocean quickly built a new bench. By June 2, it was about 90 m wide.

July 1 View is southwest across the lava bench at the Kamokuna entry a few days before the entire bench collapsed on July 6. The littoral cone in the image above is in center right. A low cliff cutting across the bench area is a headwall of a bench-collapse event that occurred in June; note the small littoral cone (immediately right of plume) that was built by tephra jets when lava entered the ocean from a lava tube. Compare the width of this new bench with the narrow remnant of a bench in the image above.

July 9 Aerial view northward of the Kamokuna entry a few days after a major bench collapse on July 6. Note the absence of a bench seaward of the littoral cone (dark "spot" in center of image left of the plume).

Diminishing Waha`ula entry point

View is southwest across the Waha`ula entry point. Since a brief pause in the supply of lava to the tube system on May 19-20, a diminishing volume of lava has reached the Waha`ula entry point. Much of the lava has entered the ocean from small surface flows that have broken out of the tube system, not directly from the tube. Plume in background marks the Kamokuna entry point.

Flow-field map showing lava emplaced during the Pu`u `O`o - Kupaianaha eruption since 1983. Note the new lava flows that were emplaced on the Pulama pali and at the Kamokuna and Waha`ula entry points following the brief pause May 19-20. This map was compiled on June 5, 1998. A few small lava breakouts have occurred near the ocean entry points between June 5 and July 9; these are not shown on the map.

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Updated: 10 July 1998