How to keep the flows out: Build a wall

by Zahra Hirji
Thursday, August 7, 2014

The upper northern slopes of Mauna Loa are a painter’s palette of red, brown and black lava rocks. A cluster of scientific buildings composing the Mauna Loa Observatory and Solar Observatory stands out with their reflective white and silver rooftops against the Mars-like backdrop.

The 1984 Mauna Loa eruption took a heavy toll on the twin observatories, knocking out the power and interrupting several experiments for nearly a month. Some equipment also suffered weathering from the eruption’s massive outpouring of sulfuric acid.

Post-eruption, the meteorologists worked with scientists at the U.S. Geological Survey Hawaiian Volcano Observatory (HVO) to design a protective diversionary structure around the observatory — which is now the only lava barrier on the island. Using the most abundant material available, the wall is composed of old lava flows bulldozed into a 300-meter-long wishbone structure that stands about 3 meters high and sits less than 400 meters upslope from the observatory.

Designed by former HVO geologist Jack Lockwood and a team of engineers, the structure was built in 1986 and takes advantage of the natural topography, enhancing existing highs and lows. In the case of a future eruption, summit flows would likely hit the wall and surge along the edge of the barrier around the observatory.

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