July 16: Lava Boat Tourists Injured

July 16, 2018. USGS: “The active ocean entry along the southernmost margin of the fissure 8 flow is a hazardous area. The interaction of lava and seawater creates “laze,” a corrosive steam plume laced with hydrochloric acid and fine volcanic glass particles that is blown downwind and can irritate the skin, eyes, and lungs. Lava flows entering the ocean can also result in explosive interactions, littoral explosions, that can hurl fragments of molten lava and rocky debris hundreds of meters (yards) inland and seaward.” (Full-sized)
Today’s Eruption Summary

The big news today was a lava tour boat getting pelted by lava chunks from an ocean entry explosion, resulting in burns, bruises, and one broken leg. Next to that, the science of this eruption seems a bit trivial. But this blog is primarily oriented towards the latter, so let’s get volcanology news out of the way first.

The Italian Space Agency released a new CosmoSkyMed radar scan of Kīlauea’s summit. Let’s hope this really is the new northern extent of Halemaʻumaʻu:

May 5-July 16, 2018. USGS: “Over time, expansion of the summit eruptive vent within Halema‘uma‘u crater and the widening of Halema‘uma‘u itself are obvious. Starting in late May, the development of several cracks outside Halema‘uma‘u is clear, and inward slumping of a large portion of the western, southwestern, and northern crater rim begins. Much of this motion appears to be coincident with the small explosions from the summit that have taken place on a near daily basis since early June. The most recent radar scene, from July 16, shows continued motion along cracks over a broader area of the caldera floor, extending east of Halema‘uma‘u. We expect this slumping to continue as long as the collapse events and overall subsidence persist.” (Full-sized)

This morning, over 24 hours after the previous summit collapse, the lava channel below Fissure 8 was full but not overflowing. Even after today’s 11:42am summit collapse, there was no observed surge— “Nothing notable in the way of overflows.” Last night’s field crews heard Fissure 22 grumbling to itself, but saw no visible signs of renewed activity.

According to Civil Defense this afternoon, the southern edge of the main lava flow has stalled 1 km from Isaac Hale Park / Pohoiki boat ramp. Just north of there, the new ocean entry at Ahalanui is vigorous and dangerous. That’s where @hotseathawaii filmed an offshore explosion four days ago. There were more explosions this morning, “with at least one being quite strong” (USGS).

(The summit collapse was M 5.3 again. The livestream is still ailing, but even so it captured rockfalls, camera shake, and the earthquake’s progression from far to near in the field of view.)

July 16 Map of Active Lava Flows

Lava delta is up to 690 acres, by the way. “Tiny no-longer-island” is next to the c in “former coastline.”

USGS map of LERZ lava flows as of July 15, 2018, 1 pm HST. Yes, the tiny no-longer-an-island is visible in the full-sized image.

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