Hawaii’s Mauna Loa volcano erupted for the first time in 38 years

No evacuation orders had been issued as of late Monday morning, but shelters were opened as a precaution, Hawaii officials said. And authorities warned that winds could carry volcanic gas and fine ash downwind.

While the eruption was initially limited to the summit of the volcano, the USGS said in a 7:20 a.m. update that lava also began flowing from the northeast side of the volcano in what scientists are calling its northeast fault zone.

Wendy Stovall, a USGS volcanologist, said that’s good news for the Kona area on the west side of the island, where the steep slopes mean it can take just hours for lava flows from the southeast Mauna Loa rift zone to to reach, making it the most vulnerable part of the island during an eruption.

“When Mauna Loa erupts, it remains in a rift zone; they usually don’t move from side to side,” she said. “The eruption should remain in the northeast rift zone.”

The volcano’s slopes on its northeast side are gradual, meaning it could take weeks or months and a large volume of lava flows for any populated area to face significant danger. Stovall said the lava flows could eventually reach a key road across the island, Saddle Road, as well as a road leading to an observatory on its northern flank, where measurements of atmospheric gases have been collected from 1950s, including carbon dioxide and methane. , known to cause climate change. The observatory itself is not at imminent risk, Stovall said.

While there were no immediate signs of dangerous lava flows or earthquake risks, both are common consequences of past eruptions, said Falk Amelung, a professor at the University of Miami who has studied Mauna Loa.

“The worst-case scenario is not good,” Amelung said, urging residents to be prepared for earthquakes and evacuation.

Earthquakes “are not among the biggest hazards we’re looking at right now,” said Wes Thelen, a USGS seismologist. However, Hawaii’s largest earthquake on record in 1868 was associated with a Mauna Loa eruption, and the links between volcanic eruptions and earthquakes are “pretty tight,” he added.

“There are cases of earthquakes triggering eruptions and possibly eruptions triggering earthquakes,” Thelen said. “But it’s not a foregone conclusion that there will be a large earthquake associated with this particular eruption.”

An ash fall warning was in effect Monday until 10 a.m. Hawaii time or 3 p.m. EST for the Big Island and across the Maui Channel to the southeast shores of Maui. The National Weather Service in Honolulu, which is about 120 miles northwest of Mauna Loa, said up to a quarter inch of ash could accumulate on the Big Island, potentially causing respiratory distress for some people , damaging motors and electronics, and damaging crops and livestock.

Eruptions in 1984 and 1950 sent lava flows toward the towns of Hilo and South Kona, respectively, the National Park Service said. Flows can take anywhere from hours to weeks or months to reach communities, according to USGS maps.

“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.

Mauna Loa, one of Earth’s most active volcanoes, has erupted 33 times since 1843, according to the USGS.

The volcano, whose name means “long mountain”, is known as a shield volcano because it is significantly wider than it is tall. Mauna Loa makes up about 51 percent of the Big Island and rises 13,681 feet above sea level and about 30,000 feet from the sea floor, according to the National Park Service.

The USGS, which has a research camera posted on the north rim of Mokuaweoweo, released images from before and after the eruption.

The eruption could also be seen from space, captured by the National Oceanic and Atmospheric Administration’s GOES West satellite.