Volcanologists struggled to contain their excitement after Mauna Loa in Hawaii, the world’s largest active volcano, awoke this week after having been dormant for nearly four decades, sending fountains of lava high into the air and down the mountain.
“It’s fabulous, really fantastic,” said Carmen Solana, a lava flow specialist at the University of Portsmouth in the UK. “We have been waiting for this for a long time. My whole career I’ve heard ‘Mauna Loa is going to burst – Oh no it’s not’. Now it really is.
Diana Roman, a volcanologist at the Carnegie Institution for Science in Washington DC, said: “The eruption [is] really important for our understanding of this type of volcanism.
Mauna Loa, which rises 4,170 meters above the Big Island of Hawaii, is one of the most studied volcanoes in the world, with more instruments on its slopes than any other. The eruption – the first in 38 years – offers scientists a unique opportunity to examine the factors that trigger the flow of magma – molten rock at a temperature of around 1,000°C – through the underground channels of the volcano and on the surface as lava. They also hope to improve their ability to predict the timing and strength of eruptions.
So far, the excitement of the spectacle and scientific opportunity has not been tempered by any significant harm or danger. Hawaiian volcanoes are typically what volcanologists call “effusive,” producing vast lava flows but not the violent explosions that characterize the most dangerous and unpredictable eruptions elsewhere.
The biggest casualty since the eruption began on Nov. 27 has been collecting data for one of climate science’s most famous records, the Keeling Curve. This 60-year record of rising carbon dioxide levels in the atmosphere is generated by instruments at the Mauna Loa Observatory, but lava flows have cut off electricity and access to the site.
Ralph Keeling, a geoscientist at the Scripps Institution in San Diego, whose late father Charles created the curve, said the outlook for future carbon dioxide readings was “very troubling. . . It’s a big blowout and it’s in a bad place.
However, the island’s 200,000 residents and passing tourists have so far been largely spared. Mauna Loa’s lava front moves slowly, at 24 meters per hour, over uninhabited ground with little vegetation.
The amounts of sulphurous gas, ash and the evocatively named but potentially dangerous Pelé’s hair – long glassy strands carried downwind as bubbles burst of molten lava – were relatively limited and diluted by the wind.
Scientists say Mauna Loa is also not likely to blast large amounts of disruptive material into the atmosphere, unlike the 2010 eruption of Eyjafjallajökull in Iceland. This sent an ash plume 9km into the atmosphere and eventually across Europe, throwing aviation into chaos for almost a month.
Volcanologists say there is also no chance of an event on the scale of the two major 19th century Indonesian eruptions – Tambora in 1815 and Krakatoa in 1883 – which killed tens of thousands of people and affected the climate. worldwide for years.
“Each volcano has its own personality,” Roman said. “In Hawaii we have two side-by-side volcanoes, Mauna Loa and Kilauea, which behave quite differently despite being connected to the same depth control system.”
Kilauea is one of the most active volcanoes in the world, with much more frequent and longer eruptions than Mauna Loa.
However, a prolonged eruption of Mauna Loa would cause significant damage, as Kilauea did when a 2018 eruption destroyed 700 homes. The lava flow could cut off Saddle Road, the main highway between the Big Island’s east and west coasts, within days if activity continues at its current rate.
Volcanologists are hesitant to predict how long the eruption will last. “If you look at the character of the volcano and its past eruptions, they’ve mostly lasted a few weeks, and that’s the overall best expectation this time around,” Roman said. “We don’t have a good tool to predict the duration.”
Currently, lava is emerging from a fissure on the northeast side of the mountain near the summit. If it continues to sink at the current rate without solidifying, it will reach Hilo, the island’s capital with a population of 45,000, within weeks.
“The worst-case scenario is fissures opening further downslope, which could cause lava to reach Hilo faster,” Solano said.
Roman said: “Another worst-case scenario would be a large earthquake, possibly magnitude seven, associated with the eruption.”
If all goes well, however, this eruption of Hawaii’s volcanic giant will provide more pleasure than pain – a spectacular demonstration of the might of Earth’s geophysical forces without human casualties or destruction of significant property.