Volcanic fumes might linger over East Hawaii for the next few days even as the latest eruption of Kilauea has paused.
The Hawaiian Volcano Observatory reported Friday evening that the most recent eruption of Kilauea — which had begun Dec. 23 — had stopped. Although seismic tremors and glow from the floor of Halema‘uma‘u crater continued through the weekend and into Monday, lava was no longer emerging from underground.
Gas emission levels were still higher than normal, however, and Hilo residents got a mouthful of vog Sunday and Monday after a shift in the winds brought a southerly breeze.
According to preliminary state Department of Health data, air quality in Hilo became noticeably worse late Sunday evening, with sulfur dioxide levels climbing from a background level of 0.002 parts per million at about 8:45 p.m. Sunday to a high of 0.036 ppm at 7:45 a.m. Monday.
DOH categorized Hilo’s air quality as “moderate,” instead of the typical “good.”
Other East Hawaii DOH monitoring stations, such as in Hawaiian Paradise Park, reported similar increases in SO2 levels.
While SO2 concentrations in Hilo appeared to diminish throughout Monday, East Hawaii could experience more vog through today and Wednesday.
National Weather Service meteorologist Thomas Vaughan said the southerly winds currently affecting the island are expected to continue through Wednesday night.
Late Wednesday or early Thursday should see a return of the typical trade winds, Vaughan said, which should push any vog westward — a boon for residents on the windward side, but will likely be a nuisance for Kailua-Kona residents.
“We actually got some vog all the way here on Oahu (during the eruption),” Vaughan said.
Of course, this depends on whether Kilauea will continue to produce elevated levels of volcanic gases.
HVO research geologist Patricia Nadeau said the volcano is producing more gas than the typical background level associated with Kilauea’s noneruptive periods, but gas levels are markedly diminished since the latest eruption.
“Unfortunately, the same conditions that are sending the vog to Hilo are making it hard to measure how much gas is being emitted,” Nadeau said.
Previous Kilauea eruptions have varied in terms of how quickly gas emission levels diminished after the eruption ended. Nadeau said gas levels following the volcano’s 2020 eruption tapered off slowly over several months, while eruptions in 2023 and 2024 saw levels decline much more quickly.
Nadeau said this latest eruption could be more like Kilauea’s single-day eruption in June 2024, which saw elevated gas emissions quickly drop off within a day. However, that eruption also emerged from a different location, outside of Halema‘uma‘u crater.
Regardless, there is no clear sign this latest eruption is actually over.
Nadeau said there are still seismic tremors from the volcano as well as infrasound — deep, low-frequency sounds below the threshold of human hearing — that indicates movement of magma and degassing beneath the surface.
If those signs fade out, Nadeau said, then HVO will begin to determine whether the eruption is officially over.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.
