Since 1843, Mauna Loa has erupted 33 times, averaging one eruption every five years. However, most eruptions occurred prior to 1950, averaging 3.5 years between eruptions. Since 1950, there have only been two eruptions; a summit eruption 25 years later in 1975 and by a rift eruption nine years later in 1984. As of 2022, it has been 38 years since the last eruption, the longest quiet period on record.
Largest Active Volcano In The World Erupts
Hawaii Island residents woke up on November 28, 2022, to news they knew might be coming. The world’s largest active volcano was awake. It is located at the edge of Hawaiʻi Volcanoes National Park at the center of the island.
The Mauna Loa eruption of 2022 happened on Hawaiian Independence Day (Lā Kūʻokoʻa), which commemorates the signing of the Anglo-Franco Proclamation of 1843. This day recognizes the independence and sovereignty of the kingdom by Great Britain and France. The United States did not join the proclamation. In 1898, November 28th was declared Thanksgiving Day, but after the annexation of Hawai’i by the United States, the holiday lost official recognition. The Hawaiian sovereignty movement celebrates this holiday to keep the movement alive and to spread awareness.
Rumblings and earthquakes have been recorded at five to 10 per day since June 2022, increasing to 10-20 daily during July and August. A peak in activity on September 23rd and 29th recorded more than 100 earthquakes per day.
What is Happening Now
The biggest concern is if the lava flow migrates to rift zones – cracks in the mountain – it poses more risk to populated areas. No mandatory evacuations exist, but shelters have opened to accommodate those leaving voluntarily. At the time of this writing, lava is overflowing into the southwest portion of the volcano’s caldera toward the Pōhakuloa Training Area – a US military training base. “Nobody is in danger at this time,” said Hawaii Island Mayor Mitch Roth.
December 2 — With all of the excitement surrounding the Mauna Loa eruption, the impact of people trying to get a glimpse is causing major traffic problems. Hawaii Island Mayor Mitch Roth is reminding the public about the safety rules.
On Tuesday, November 29, the Hawaii Fire Department responded to an incident around 9:05 p.m. Six patients were said to be involved, two needing medical transport for minor injuries. A medic on board said the injured patients were idled along the shoulder when they were hit as they tried to pull back onto the main roadway.
Hawaii police confirmed 14 citations were issued Tuesday night, and police will continue to give out tickets to those who park along mile markers 16 to 31 on the highway. A primary concern is people walking across the road and cars pulling out in front of traffic.
Mayor Roth said, “People are bringing their kids up, and 60 mph and kids and cars on the highway are just a recipe for disaster.”
Parking along Saddle Road remains off-limits, but that hasn’t deterred people from trying. There is one designated parking area off a military training facility (Pōhakuloa Training Area), but being on federal land and a poorly-maintained road are two issues.
As of Thursday morning, December 1st, a new route was worked out with the state and Pōhakuloa Training Area. The entry to the 4.5-mile, one-way route is across from Gilbert Kahele Recreation Area, with its exit at a junction point on the highway just before the Pu‘u Huluhulu volcanic cinder cone near the Maunakea Access Road.
Lava viewing will be constrained to the route, which provides clear visual access to the mountain and the ongoing lava flows. Parking also will be allowed on the side of the road; however, only on the right side, and no vehicle can remain in the area for more than 90 minutes. Still, the best option for visitors is the Hawaii Volcanoes National Park which remains open 24/7. “You get two volcanoes for the price of one. You have one Halemaumau (Kilauea), and you’re looking up at Mauna Loa and seeing the eruption up there. It’s quite spectacular,” said Roth.
December 1 — Hawaiian Volcano Observatory said field crews had been deployed to monitor the situation closely. USGS said the early stages of Mauna Loa eruptions tend to be “very dynamic,” and lava flow advances can change rapidly. “This is still a summit eruption,” said Ken Hon, Hawaiian Volcano Observatory scientist-in-charge.
“We would encourage everyone who has plans to visit the island to continue. It is completely safe. The eruption site is high up the mountain, and it’s in a relatively isolated location,” Governor Ige told CNN on November 30th.
There are currently two active fissures, with fissure 3 being the dominant source. Magma is still being supplied to the fissures, so activity will continue as long as tremors persist. It’s moving at a rate of 0.2 miles per hour (24 meters per hour). Forecasts indicate that the lava flow could take two days to reach the Daniel K. Inouye Highway (Saddle Road), the major highway between Hilo and Kona. There have been lava diversion discussions without a solid plan, though officials continue to make the best course of action.
“It’s a volume problem. You’re going to store up a certain amount of lava somehow. The places that they’ve had some success are mainly in Italy, where they’ve done a fair amount of work on this. You need a very geographically constricted area if you’re going to dam the lava up, but it’s just like damming water, and they were successfully able to dam it up for a few months, but it eventually overflowed the dams… Nobody’s really had a lot of success with that,” Ken Hon, Scientist-In-Charge USGS Hawaiian Volcano Observatory, said in a video call on November 30th.
Ash and Pele’s Hair
While an earlier ash advisory is no longer in effect, scientists said winds might carry volcanic gas, fine ash, and Pele’s hair downwind. Officials urge those with respiratory sensitivities to take precautions to minimize exposure.
Pele’s hair (closest modern Hawaiian translation: lauoho o Pele) is a volcanic glass formation produced from cooled lava stretched into thin strands, usually from lava fountains. It is named after Pele, the Hawaiian goddess of fire and volcanoes.
It is common to find strands of Pele’s hair on high places like treetops, radio antennas, and electric poles. Wind often carries the light fibers high into the air and to places miles away from the vent. Mentions of this type of lava can be found in 18th Century Hawaiian newspapers.
Mauna Loa History
Mauna Loa, which rises 13,679 feet (4,169 meters) above sea level, has erupted 33 times since 1843. It’s the first eruption of Mauna Loa since 1984 – making this prolonged quiet period the volcano’s longest in recorded history.
During that eruption, fissures eventually opened on the mountain’s northeast rift zone, sending lava flows snaking toward the Hilo area. None of the flows reached the outskirts of Hilo by the time the eruption ended, about 20 days after it began.
Mauna Loa is not known to have produced an explosive eruption since 1843, but there is geologic evidence of some explosive activity in the past 1,000 years. Pāhoehoe is basaltic lava with a smooth, billowy, undulating, or ropy surface. Geologists have identified at least four debris fans of fragmented rock deposits on top of pāhoehoe lava flows spreading from the summit.
The Nīnole Hills are steep-sided and heavily vegetated flat-topped ridges located on the southeastern flank of Mauna Loa. Age dating and chemical analysis of lava flows exposed in Nīnole Hills indicate they erupted about 125,000 years ago from Mauna Loa.
Detailed geologic mapping and dating of lava flow above sea level show that about 90 percent of Mauna Loa’s surface is covered with flows that erupted within the past 4,000 years. Hundreds of lava flows erupted during this time, but they did not cover the volcano evenly. By tracing the flows back to their vents and knowing their ages based on radiocarbon dating, geologists have recognized a general pattern in the frequency of lava flows spreading from the summit area and the rift zones during the past few thousand years.