U.S. Geological Survey - Hawaiian Volcano Observatory
Kilauea - Eruption Summary - Hazards - History
This update current as of September 4, 1998. Eruption updates are posted every 4 to 6 weeks; more frequent updates will be made when there are drastic changes in activity or when residential areas are threatened by lava flows.
Aerial view to south shows pathway of new pahoehoe lava (shiny surface, foreground) that reached the sea on August 30. The new entry area is about 300-400 m west (right) of the long-established east Kamokuna entry (left steam plume rising from beyond littoral cone, which is fed by a lava tube).
Lava continues to erupt from vents on the southwest flank of Pu`u `O`o and travels 12 km to the coast through lava tubes. Lava breakouts from the tubes, following a pause in magma supply to Pu`u `O`o on August 12-14, led to a new pahoehoe flow at the base of the pali. The flow front was about 500 m from the shoreline on August 25 and reached the sea five days later. The broad flow is slowly inflating and a new lava tube is developing within the flow. Both the new tube and surface flows deliver lava to the sea at the new entry area.
Lava has been spreading as many small pahoehoe toes from along the margins of the new flow upslope from the shoreline. The new flow is extremely hot and makes the approach from the west difficult and hazardous (west access is from the end of the Chain of Craters Road in Hawai`i Volcanoes National Park). Lava at the new entry intially poured over a sea cliff created by a previous bench collapse and onto a black sand beach. Both entries are adding new lava to the Kamokuna bench. Visitors should be wary of collapses and explosions that can occur suddenly along the growing lava bench.
Twenty pauses lasting from a few hours to a few days have occurred so far during Episode 55, which began in March 1997. These short-term interruptions in magma supply to Pu`u `O`o result from one or more blockages in the conduit system between the summit magma reservoir and Pu`u `O`o. The most recent pause (No. 20) began on August 12 and lasted approximately 42 hours, during which time Kilauea's summit inflated about 2 microradians. The slight inflation indicates magma was still rising into the summit reservoir but not moving into the east rift zone.
When lava emerged again from Pu`u `O`o and flowed back into the tube, several flows broke out on the pali and at its base. The largest flow originated from the same breakout point that was active following a pause in July.
Seismologists noted a series of more than two dozen seismic signals localized at Pu`u `O`o on August 26. The signals had a frequency lower than is typical of that for most earthquakes, and they were likely caused by the partial collapse of a spatter cone located on the west flank of Pu`u `O`o.
August 27. Aerial view of the Episode 55 spatter cone located on the west flank of Pu`u `O`o (out of view to left). The low notch represents a missing part of the cone that collapsed, probably on the previous day.
September 3. By September 3, the crater atop the spatter cone had grown to about 50 m in diameter.
Map showing area covered by lava flows emplaced during the Pu`u `O`o - Kupaianaha eruption between 1983 and August 30, 1998. Flows emplaced between August 14 and August 30 are shown in purple. A new lava tube is developing within this flow area and is delivering lava to the sea 300-400 m west of the east Kamokuna lava tube (black line).