Volcano Watch — How the lava viewing got to be so great

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The past two weeks have been exceptional for viewers of Kilauea's lava flows. Both colorful and convenient, the flows have drawn visitors to the island and attracted many residents as well. How did this happen?

lava bench, showing lava entries on east side of leading tip of bench.

 Wilipe`a bench.View at 0543, August 1, 2002 from east end of bench, showing lava entries on east side of leading tip of bench. (Public domain.)

Visitors watch lava flow cover black sand beach

Visitors watch lava flow cover black sand beach at west end of Wilipe`a bench, 0604. (Public domain.)

Everything started on Mother's Day, May 12, when a new vent opened near the southwest base of Pu`u `O`o. This area had not been the site of a previous vent, but nearby areas hosted many small vents during the past several years.

The Mother's Day flow poured southwest into the nearest forest, turned south-southeast, and began its long, slow descent through the forest to the coastal flat below Paliuli. Along the way, the flow started the 3,600-acre Kupukupu fire, which burned throughout much of June and has had flare-ups since. By early June, lava had crossed the Kalapana Trail and almost reached the top of Paliuli. A park trail was readied for the time when the lava would pour down the pali onto the coastal flat and be easily accessible to visitors.

Lava cascades started down Paliuli on the night of June 9-10, 1.5 km (1 mile) from the coast. For the next five-and-a-half weeks, the flow fed by the cascades slowly worked its way across the coastal flat, feinting this way and that, first to the west, then to the east, then in the middle. By June 25, an arm had moved along the west side of the 1995 flow to within 450 m (1,500 feet) of the Chain of Craters Road. It looked as if the flow were going to continue, and several small buildings at the end of the road were moved.

But the threatening flow stagnated, and all activity became concentrated in the central and eastern parts of the 1-km-wide (0.6-mile-wide) flow front. By June 30, the leading edge of the flow was 1 km (3,300 feet) from water; by July 5, 800 m (2,600 feet); by July 10, 550 m (1,800 feet); and by July 15, 400 m (1,300 feet).

Then, two fingers of the eastern lobe really took off. The west finger led on July 16-18, but the east rapidly closed in and was only 10 m (30 feet) shy on the 18th. That evening, a final push sent lava from the east arm into the ocean, at a place we now call West Highcastle.

Meanwhile, a rapidly developing western arm of the flow was surging seaward, along the general route of the June threat. By morning of July 19, its front was 700 m (2,300 feet) from the Chain of Craters Road. The front moved 400 m (1,300 feet) in the next 20 hours and then 300 m (1,000 feet) in the next 12 hours, crossing the road in the early evening. Fortunately, the park had just enough time to move the building over the lua before it was destroyed. The lava quickly poured the next 230 m (750 feet) and entered the water in the early morning hours of Sunday, July 21, at a place known as Wilipe`a.

The Wilipe`a entry quickly built a large bench, which at this writing reaches about 90 m (300 feet) offshore and is 470 m (1,540 feet) wide along the shore line. Visitors have outstanding viewing across the west end of the bench with favorable wind. If stinging acidic steam covers that area, visitors can take a marked trail across the warm flow to an upwind vantage point on the east side of the bench.

Talk about a media splash! Amid the many truths, one misconception stands out. The flow is NOT the most dangerous in years. Lava flows have been entering the water off and on for the past 16 years, and each had a similar set of hazards. The current activity is not exceptional, but it is easily accessible. More people are therefore at risk, but the hazards they face are no greater than before. The difference between hazard (a natural process or event) and risk (the impact on society) is often confused. To the individual, there is no greater danger than before. To society, there are more people observing the entry, so there is more chance of someone getting hurt.

How long will the great viewing last? Probably not long, so enjoy it while you can!

Volcano Activity Update

Eruptive activity of Kilauea Volcano continued unabated at the Pu`u `O`o vent during the past week. As mentioned above, both the West Highcastle and Wilipe`a ocean entries of the Mother's Day flow are active and forming benches. More than seven acres of new land have been mapped in the first 10 days since lava reentered the ocean, and the area is rapidly increasing and adding to the size of the island. Lava viewing is spectacular, and the National Park Service is allowing visitors to hike out and get up close to the active flows.

The eastern Boundary flow emanating from the "rootless" shields remains prominent. Two incandescent streams are seen on Pulama pali from just above to one-third of the way down.

Two earthquakes were reported felt during the week ending on August 1. A resident on Kama`ili Road in Puna felt an earthquake at 6:33 p.m. on July 25. The magnitude-2.4 earthquake was located 5 km (3 mi) north of `Opihikao at a depth of 5.9 km (3.5 mi). A magnitude-2.0 earthquake located 2 km (1.2 mi) south of Pa`auilo at a depth of 8.1 km (5 mi) was felt by a resident of Papa`aloa at 7:52 p.m. on July 30.