The world's largest volcano, Hawaii's Mauna Loa, has started to erupt after months of unrest, following a 38-year period of silence.
Downslope communities have been warned to prepare for potential lava flows following a U.S. Geological Survey announcement made at 11:30 p.m. HST on November 27.
Mauna Loa's last eruption took place on March 25, 1984. It began at 1:25 a.m. local time at the Moku'āweoweo summit caldera—a large crater at the top of the volcano. Within hours, a new fissure had opened up further down the mountain, which rapidly extended along the northeast flank, creating an explosive curtain of fire over a mile long.
Fiery fountains from this crack reached heights of up to 165 feet and gave rise to four parallel lava flows, moving at speeds of up to 700 feet per hour.
On day two, the lava in the most active flow had advanced 5.5 miles toward the city of Hilo, while the other three were on course for Kulani Prison. The prison was put on high alert as the flows came within two miles of its gates. Luckily, the lava in these flows stopped advancing within 48 hours and the prison was spared.
However, the primary flow heading to Hilo continued its rapid advance. In just four days, the lava had moved nearly 16 miles, coming within just four miles of the city.
The concerned residents of Hilo could smell smoke from the burning vegetation, hear loud explosions of methane from the advancing lava, and see an intense red glow on the horizon. Luckily, by mid-April, the lava supply began to diminish and the fiery output of the volcanic vents began to slow.
On April 15, after 21 days, the eruption was officially declared over and the people of Hilo were spared.
Nobody was hurt in the eruption, but the lava flow caused significant disruption, blocking roads and damaging power lines.
The USGS said that the present eruption is currently contained to the volcano's summit crater and isn't yet a threat to the downslope communities. However, up to a quarter-inch of ash is expected to coat the island of Hawaii and it isn't yet known how the eruption will progress.
"Based on past events, the early stages of a Mauna Loa eruption can be very dynamic, and the location and advance of lava flows can change rapidly," the USGS said in an update. "If the eruption remains in Moku'āweoweo, lava flows will most likely be confined within the caldera walls. However, if the eruptive vents migrate outside its walls, lava flows may move rapidly downslope."
The situation is being carefully monitored by the Hawaii Volcano Observatory and emergency management partners.
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Pandora Dewan is a Senior Science Reporter at Newsweek based in London, UK. Her focus is reporting on science, health ... Read more
