The world’s largest active volcano, Mauna Loa in Hawaii, has erupted for the first time in almost 40 years. US officials are warning nearby residents to prepare for possible evacuation.
The eruption started at 11:30pm local time on November 27th at Moku‘āweoweo, the summit’s caldera located inside Hawai‘i Volcanoes National Park on the island of Hawaii. This is the first eruption since 1984.
As of now, the eruption is limited to the summit area. However, officials have cautioned that the situation could change rapidly.
Mauna Loa has two rift zones, extending northeast and southwest from the caldera, where the volcano’s surface can crack and split. Ken Hon at the Hawaiian Volcano Observatory explained that “very fluid and fast-moving lava” can quickly flow from a new fissure, posing a threat to populated areas downstream. It is uncertain whether the eruption will remain confined to the summit or extend to one of the rift zones.
On November 28th, officials from the US Geological Survey reported that lava had started to spill out of the summit’s caldera, but there is currently no evidence of lava erupting from the rift zones.
Ashfall warnings have been issued for Hawaii’s Big Island, and medically vulnerable residents are advised to stay inside or wear filter masks. Shelters have been opened to provide safety for islanders, although populated areas are not immediately at risk, according to officials.
Mauna Loa is a massive shield volcano, standing at approximately 4 kilometers tall and covering a land area of about 5000 square kilometers. It has erupted 33 times since 1843, with the most significant eruption occurring in 1950.
Over the past month, volcanologists have observed increased activity at Mauna Loa, including dozens of small, shallow earthquakes around the summit. The eruption confirms their suspicions that the volcano was becoming more active. Aerial reconnaissance will be conducted by the Hawaiian Volcano Observatory to better understand the risks associated with the current eruption.
This eruption may provide valuable insights into the connection between Mauna Loa and another Hawaiian volcano called Kīlauea. Scientists are particularly interested in understanding how magma separates and flows to the two volcanoes. The delay in Mauna Loa’s last eruption may be explained by magma being diverted to Kīlauea, which experienced a major eruption in 2018 that caused a caldera collapse.
Although there is no indication that the Mauna Loa eruption will be as forceful as the 2018 Kīlauea eruption, residents are urged to stay informed and prepared.
