September 13, 1996

A weekly feature provided by scientists at the Hawaiian Volcano Observatory.

Eruption Status and Shoreline Hazards

The current Kilauea East Rift Zone eruption, which began in January 1983, continues without significant changes. The flow field now covers 23,475 acres, and 540 acres of new land have been added to the island since lava began entering the ocean in late 1986. Since early 1992, the eruption has been fed by vents, 10 miles from the summit, on the southwest flank of the Pu`u `O`o cone. The current vent feeds directly into lava tubes, which transport lava to the ocean in Hawaii Volcanoes National Park.

A total of approximately 820 acres of the flow field have been resurfaced by new lava since the beginning of June, when the eruption restarted after a five-day pause. Over the last four months, the tube feeding an ocean entry at Lae`apuki has matured into the sole pipeline to the coast. This tube survived a short eruptive pause on August 21. Since then, there have been no surface flows, and lava has been confined to the tube system.

As has been the case with other long-lived ocean entries, bench collapses of various extent at Lae`apuki have increased in frequency and are now occurring about once every two weeks. After each collapse, a severed lava tube or incandescent fault scarp is exposed to the surf, and violent explosions ensue.

Types of explosive events observed at Lae`apuki since mid-august include sudden rock blasts, sustained and powerful steam jets, lava fountains and "bubble-bursts" from holes in the tube above the entry. These events often provide visitors to the end of the Chain of Craters road a spectacular view. However, the road will be closed to the end of September, and visitors must wait until resurfacing work is completed to view the lava.

There were two felt earthquakes during the past week. Both temblors occurred on Wednesday morning, September 11. The first shaker at 3:34 a.m. was felt in Kurtistown, Hilo, and Orchidland Estates. It had a magnitude of 3.5 and was located 17 miles east of Hilo at a depth of 25 miles. The second at 8:18 a.m. had a magnitude of 3.7 and was felt in Leilani Estates and the Volcano area. The epicenter was 14 miles south of Kilauea summit at a depth of 18 miles. There was no damage reported.