Lava Delta Collapse 10-2-16

Lava Delta Collapse at Kamokuna Ocean Entry:

Lava delta collapse is one of the most dangerous phenomena associated with lava viewing at an ocean entry. Yesterday evening, a small portion of the currently active eastern Kamokuna Ocean Entry lava delta collapsed into the sea, sending enormous billows of steam and fragments of hot lava into the air higher than the approximately 60′ tall ocean cliff edge.

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Aerial views of the Kamokuna Ocean Entry with growing lava delta on September 30th. – Photo: USGS-HVO

At first, a section of the outer delta, which we estimated may have been about 60 feet long, began to tilt seaward. Before we could actually see it go into the water, huge amounts of steam shot up and a series of 15 to 20 separate explosions began, which hurled showers of hot lava bombs high into the air. Many of these blobs of hot molten lava landed right on the cliff edge, which Hawai’i Volcanoes National Park rangers recently, and wisely, roped off in anticipation of just such a collapse.

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The dotted line represents the farthest documented distance that debris was thrown from known lava delta collapses. -Map: USGS-HVO

This dotted line, which appeared on a recent HVO map, shows the maximum distance that flying debris has been documented due to lava delta collapse from Pu’u O’o’s 33 year eruption history. It’s about 790 feet (300 m) from the delta itself. Park rangers are using this as a guideline for placing their rope barriers to keep visitors safe. Although some park visitors disregard the boundary rope thinking they can get a better view, the truth is there are better vantage points out of harm’s way.

Yesterday’s explosive bench collapse, although small, was a a potent reminder to everyone there that safety is paramount in this ever changing environment.

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This recent aerial photo and thermal image clearly show cracks within the lava delta where possible collapses may occur. – Photo/Image: USGS-HVO

Immediately as the portion of the delta went into the sea a very large wave was generated which radiated outward from the cliff base. The face of the long wave was quite tall, perhaps 15 – 20 feet, although it was difficult to see because the steam and explosions obscured the view. But the very loud roaring sound from the wave was heard by everyone there, even above the noise of the continual explosions.

The portion of the lava delta that went into the sea was actually a small part of the whole, which has now reached almost 13 acres in size and is still growing. We can only imagine what a larger collapse would be like.

Our guests had a great view of this amazing event from behind the ocean entry safe zone marked by Hawai’i Volcanoes National Park rangers. Lavaland Hawai’i will get you to the lava flow with the best activity available and the best views in safety on our Lava Bike and Hike Tour.

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  • Lava Activity Update

    Hawai'i Volcanoes National Park remains closed due to the current volcanic activity but we're hopeful we'll be able to resume tours soon. We'll post any new information here as we receive it. Please check back!