USGS: Kilauea lava flows as high as condos could take decades to fully solidify

HONOLULU (HawaiiNewsNow) - It’s been nearly six months since the Kilauea eruption in lower Puna stopped.

But scientists say it could be years ― or even decades ― before the lava that flowed into the lower east rift zone, destroying hundreds of homes and forcing thousands to flee, cools enough to solidify.

The Hawaiian Volcano Observatory came to the conclusion after studying the temperature of lava in the eruption, a previous study on cooling, and analyses of eruption flow thicknesses.

Rainfall amounts, air and ground temperatures and even wind speeds can also affect how fast it takes lava to cool.

[Read more: Big Island authorities crunched the numbers on the Kilauea eruption. Here’s what they came up with]

One incredible example from the 1959 Kilauea Iki eruption: A 440-foot-deep lava lake took about 35 years to solidify “and the interior of the lake could still be hot enough today that the rock is incandescent," the observatory said.

All that means that U.S. Geological Survey scientists aren’t entirely certain when the lower east rift zone lava will cool.

But they do have some good estimates:

• The lava that erupted last year at the average flow thickness of around 33 to 50 feet could take up to 18 months to solidify.
• Lava flows that were 65 to 100 feet thick, however, could take 2 1/2 years to six years to harden.
• And the thickest flows on land ― of about 180 feet ― may not fully solidify until 2040.

The observatory noted that while it may take years for the lava to solidify “it will take much longer for the flow to cool to ambient temperatures.”

Why so long?

Well, simply put, because lava is really, really hot.

The lava that erupted into the lower east rift zone last year reached a maximum temperature of 2,080 degrees Fahrenheit. When the entire flow cools to about 1,080 degrees, it solidifies.

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