No panic, but vigilance to have. US authorities have raised the alert level around the Mauna Loa volcano in Hawaii, and civil protection teams are preparing residents for evacuation. “If you see the top glowing, you grab your things and jump in the car”warns Frank Trusdell, a Hawaiian geologist, from the AP news agency.
A shield volcano with very flowing lava
Mauna Loa, on the main island of the archipelago, is one of the largest active volcanoes in the world. Since mid-September, instruments at the top and on the sides of the mountain have been detecting tremors and deformation of the ground. For American scientists monitoring the volcano, these signs indicate that the magma chamber is filling up.
No cataclysmic eruption to be expected, however, because “this volcano is of the shield type, with a very fluid basaltic magma that flows a lot but does not explode”describes Michel Grégoire, director of research at the Toulouse environmental geosciences laboratory and lava specialist. “The most dangerous volcanoes are the explosive ones, like in Indonesia or Mount Saint Helens in the northwestern United States. »
New residents unprepared for risk
Depending on where the lava will flow from, an eruption of Mauna Loa could still threaten homes. Its last eruption dates back to 1984, and had no casualties. But since then the island’s population has doubled, and authorities fear the new residents are unprepared. The main difficulty lies in the evacuation because there is only one road. If this is cut by a flow, it is necessary to be able to redirect the populations. “We cannot give instructions at the moment, because everything will depend on the eruption recognized Ken Hon, a Hawaiian scientist, on local television.
Lava flows along the steeper southwestern flanks could reach homes within hours. Along the northeast flanks, on the other hand, they would not threaten the inhabitants for several days, leaving time to flee. The speed and amount of magma will also play a role. “At its exit point, the lava goes fast, but it cools and freezes, so the further you get from the outpouring, the slower it is”describes Michel Grégoire.
The immediate proximity of another volcano, Kilauea, which has been spewing its lava since September 2021, should not cause a “super-eruption”, even if, in places, flows can mix. Hawaii is known to be a hotspot, a place where heat anomalies from the area between the Earth’s core and mantle cause magma to rise.
Source : BBN NEWS