# Photo and Video Chronology - Kīlauea - February 24, 1998

Release Date:

Bench collapse, temporary draining of lava tube are prominent events of the past three weeks

[This update current as of February 24, 1998. Eruption updates are posted approximately every two weeks. More frequent updates will accompany drastic changes in activity or increased threat to residential areas.]

In the three weeks since February 4th,

• The eruption has returned to the sequence of events that characterize steady-state activity on the east rift zone. For example, seismicity has been low. The summit of Kilauea Volcano has shown almost inflation or deflation because magma is able to move through shallow conduits en route to the east rift zone without disturbing the ground surface.
• A bench collapse at the Kamokuna coastal entry occurred sometime between February 16 and 19. Most of the bench was destroyed when it subsided into the ocean.
• Supply of lava to the tube system was interrupted briefly on Saturday, February 21. As a consequence, the coastal steam plumes dwindled away for most of the day.

The Puu Oo vent area has remained relatively unchanged in February. Fumes issue from cracks in the cone and surrounding area. In the past month, fuming from new cracks near the north rim (right side of previous photo) has masked the view of our remote surveillance cameras. Even helicopter overflights are commonly greeted with such profuse fuming that little of the crater vent may be visible at any one time.

Lava travels in tubes from the Puu Oo vent area to the ocean. Surface lava flows have been sparse in the past three weeks. A small flow has issued every 4-5 days from the lava tubes across the coastal plain. These flows escape from weak points in the tube roof. Most breakouts have been near the Wahaula ocean entry. The photo above shows a skylight and five-week-old lava flow on the upper flow field.

Lava from the ongoing eruption enters the ocean at two sites. New land is built in these areas as the lava progrades seaward. Wahaula, the easterly site, is named for a heiau (ancient Hawaiian temple) that was overrun by lava in August 1998.

The westerly site at Kamokuna shows many features characteristic of the lava-ocean interface. A 10- to 15-m-high cliff borders the ocean, and the new land forms a low shelf or bench at the foot of the cliff. The bench grows seaward, but the steep submarine slope favors periodic failure when the bench becomes too massive. At these times, the bench and its substrate collapse abruptly into the ocean. Such a collapse occurred most recently sometime between February 16 and 19, destroying 4 hectares (10 acres) of land that had been built since the previous collapse five weeks earlier on January 15.

Eruption-viewing opportunities change constantly, so those readers planning a visit to the volcano should contact Hawaii Volcanoes National Park for the most current eruption information (ph. 808-985-6000). Additional photographs and descriptions of east rift eruptive activity may be found on the University of Hawaii's web site.

This map current as of February 20, 1998.