Tale of Two Flows
Not so long ago, I attended a meeting in Maui. At the reception the barista served a cold rum concoction called “Lava Flow”. Truth to say I sampled several, however I’m here now to tale about that second kind of lava flow, the hot one.
Pu’u ‘O’o crater lies in the Southeast rift zone of Kilauea Volcano on the Hawaii’s Big Island. Perhaps you have heard of it? Pu’u ‘O’o has been actively spilling lava since 1983 and has recently been in the news again.
Sure, lava flow hazard might be way, way down on your list of concerns, but for folks living in the Kalapana region on the Island’s south shore, the danger is as real as can be. In three decades of eruptions, hundreds of residents have seen property and homes vanish under their unstoppable onslaught.
I thought that it might be interesting to construct a computer simulation of a Pu’u ‘O’o lava flow. As always, natural hazard simulation serves planning and mitigation but it also has educational functions. In this instance, the latter might be especially relevant as the closest many of us have gotten to hot lava was in a Hawaii Five-O episode.
I’ve blogged here previously about dam-break floods. Lava flow simulation is similar and different; similar in that both deal with fluid-like material running downhill under gravity’s influence, different in that:
(1) Dam break floods usually last about an hour. Lava flows can persist for days, weeks or months.
(2) Dam break floods race down at tens of meters per second. Lava flows snail along at centimeters per second.
(3) Dam break floods just keep on going. Lava can “freeze solid’’ requiring subsequent flow to pass over or around.
Please take a look at my simulation. The volume rate of lava production in this is many times typical, so what you see might represent a long sequence of separate flows rather than one. Still, I think that you can easily appreciate how Pu’u ‘O’o has buried the Royal Gardens subdivision and the Chain of Craters Road along the coast.
All this talk of hot lava has made me thirsty for a Flow of the first kind. I wonder if I have any rum in the cupboard?
Movie link here: http://es.ucsc.edu/~ward/lava_flow.mov
You Tube link here:
Steven N. Ward Santa Cruz
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John Rundle is a Distinguished Professor of Physics and Geology at UC Davis and the Executive Director of the APEC Collaboration for Earthquake Simulations. He chaired the Board of Advisors for the Southern California Earthquake Center from 1994 to 1996. Read John's blog.