Lava shoots 100 to 200 feet into the air as Hawaii’s Mauna Loa, the world’s largest active volcano, erupts for the first time in nearly 40 years.
HONOLULU (AP) — Lava shoots 100 to 200 feet (30 to 60 meters) into the air as Hawaii’s Mauna Loa, the world’s largest active volcano, is erupting for the first time in almost 40 years.
At the moment, the lava does not threaten houses or settlements, and there have been no evacuation orders. Lava can eventually reach neighborhoods as it flows down, although it may take a week or more for the molten rock to reach populated areas.
Mauna Loa spews sulfur dioxide and other volcanic gases. They form volcanic smog, or vog, when they mix with steam, oxygen, and dust in sunlight. As a result, public health authorities are urging people to reduce outdoor exercise and other activities that cause shortness of breath.
Mauna Loa last erupted in 1984. Its smaller, more active neighbor, Kilauea, has erupted continuously for over a year since September 2021.
WHERE IS MAUNA LOA?
Mauna Loa is one of five volcanoes that together make up the Big Island of Hawaii, which is the southernmost island of the Hawaiian archipelago. It’s not the tallest (that title goes to Mauna Kea), but it’s the largest and makes up about half of the island’s landmass.
It is directly north of the Kilauea volcano, which is well known for its 2018 eruption that destroyed 700 homes and sent rivers of lava spilling over farms and into the ocean.
The last eruption of Mauna Loa was 38 years ago. The current eruption is the 34th since recorded history began in 1843.
The Big Island is mostly rural and home to cattle ranches and coffee farms, but it is also home to several small towns, including the county seat of Hilo, which has a population of 45,000.
It is about 200 miles (320 kilometers) south of Hawaii’s most populated island, Oahu, home to the state capital Honolulu and the beach resort town of Waikiki.
Tom Mauna Loa is estimated to be at least 18,000 cubic miles (75,000 cubic kilometers), making it the largest volcano in the world when measured from the ocean floor to its summit.
WHERE DOES MAUNA LOA COME FROM?
The eruption began on Sunday night at the summit after a series of strong earthquakes. It then spread to vents formed in the rift zone, where the mountain breaks apart and magma escapes more easily.
These vents are on the northeast side of the mountain, and lava coming up from there can head toward Hilo, which is on the east side of the island.
Ken Hon, chief scientist at the Hawaiian Volcano Observatory, said he doesn’t expect any additional vents to form in the volcano’s southwest rift zone during this eruption. This means that this time the settlements in the west will be free of lava flows.
Mauna Loa also erupted from the northeast in 1984. This time the lava headed toward Hill, but stopped a few miles from town.
Historically, each eruption of Mauna Loa has lasted several weeks. Hohn expects the current eruption to follow this pattern.
IS MAUNA LOA EXPLODING LIKE MOUNT ST. ALLENS?
Mauna Loa does not erupt like Mount St. Helens in Washington state did in 1980, killing 57 people. That eruption sent ash over 80,000 feet (24,384 meters) and rained down 250 miles (400 kilometers).
The magma at Mount St. Helens tends to be more viscous and traps more gas, making it more likely to explode as it rises. These are a type called composite volcanoes that form concave cones.
Mauna Loa magma is generally hotter, drier, and more fluid. This allows magma gases to escape and lava to flow down the sides of the volcano, as it does now. Mauna Loa is a shield volcano, so named because the long, sweeping slopes created by repeated lava flows give it the appearance of a warrior’s shield.
In 1989, Redoubt Volcano in Alaska, another composite volcano, spewed an 8-mile ash cloud which killed all four engines of a KLM Royal Dutch Airlines plane. The plane plummeted from 13,000 feet before all engines restarted and the plane landed without harm to the 245 people on board.
This time, Mauna Loa emitted some ash, but in a much smaller volume than these examples from complex volcanoes.
WHAT IS THE DANGER OF MAUNA LOA Eruption?
-Lava: Molten rock can cover houses, farms, or neighborhoods, depending on where it flows. But lava from the northeast rift zone is likely to take at least a week to reach populated areas, giving people time to evacuate if necessary.
-Volcanic Gas: Mauna Loa emits volcanic gases, mainly sulfur dioxide. Gases are present in greatest concentration near the top of the crater or vents. But they also combine with other particles to form Vogwhich could spread across the Big Island and even move to other islands in the state.
Vog can cause burning eyes, headache and sore throat. It can send people with asthma or other respiratory problems to the hospital.
– Particles of Glass: When hot lava erupts from a fissure and cools rapidly, forms glass particles named “Pele’s hair” and “Pele’s tears” after the Hawaiian goddess of volcanoes.
The particles typically don’t travel far from volcanic vents — maybe only a few hundred yards or miles — and won’t pose a threat to many people, said Aaron Petrushka, associate professor of Earth Sciences at the University of Hawaii.
“It literally looks like strands of hair. And that’s where the flowing lava is stretched by the wind to make long, thin threads,” Petrushka said.
Shards of glass — as short as a few millimeters or several inches long — can be sharp.
“You wouldn’t want to dig into it with your hands because you might get a cut,” Petrushka said.
An N95 or KF94 mask will protect against these glass particles, but not against volcanic gas, said Dr. Libby Char, director of the state’s health department.
Specimens of “Pele’s hair” from the Kilauea eruption are visible in Hawaii Volcanoes National Park.
HOW SIGNIFICANT ARE MAUNA LOA’S GREENHOUSE GAS EMISSIONS?
Mauna Loa emitted about 15,000 tons of carbon dioxide per day during its 1984 eruption, according to the USGS.
It is equivalent annual emissions from 2,400 sports cars.
Scientists say that all of Earth’s volcanoes combined emit less than one percent of the carbon dioxide produced by humans each year.
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This story corrects the Mauna Loa volume number to be measured in cubic miles (cubic kilometers) rather than square miles.
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