An enormous and continuous plume of dark ash began spewing from a fissure on Hawaii's Kīlauea Volcano with increased intensity on Tuesday. This prompted the USGS to issue a red alert for aviation, warning airlines and pilots to avoid the volatile area.
Aviators need to be wary of airborne ash, as the particles are large enough to impact the aircraft's engines and cause engine failure.
The ash cloud reportedly reached as high as 10,000 to 12,000 feet above sea level. The height varied depending on the strength and direction of the wind, with falling ash and increased vog reported in Pahala, a town 18 miles downwind of Kīlauea, according to the USGS.
The USGS reported that ash emission greatly decreased on Wednesday.
There are now 20 active fissures that have cracked open since the volcano's eruption on Thursday, May 3, and 37 structures have been destroyed.
This photo from the U.S. Geological Survey shows activity at Halema'uma'u Crater that has increased to include the nearly continuous emission of ash with intermittent stronger pulses at Hawaii Volcanoes National Park on the island of Hawaii at around 9 a.m. Tuesday, May 15, 2018. Plumes range from 1 to 2 kilometers (3,000 to 6,000 feet) above the ground. Officials on the Big Island of Hawaii say some vents formed by Kilauea volcano are releasing such high levels of sulfur dioxide that the gas poses an immediate danger to anyone nearby.(U.S. Geological Survey via AP)
Hundreds remain evacuated from the Leilani Estates community, with more businesses closing and evacuations ordered with each new fissure.
The observatory also remains concerned for the possibility of an explosive eruption at the volcano's Halema'uma'u Crater.
"At any time, activity may become more explosive, increasing the intensity of ash production and producing ballistic projectiles near the vent,"according to the USGS observatory notice from Tuesday afternoon.
"This could generate dangerous debris very near the crater and ashfalls up to tens of miles downwind,"the Civil Defense Agency stated.
Toxic gases rise from cracks in the Leilani Estates subdivision near Pahoa, Hawaii, Friday, May 11, 2018. (AP Photo/Jae C. Hong)
Winds are expected to direct the hazardous vog mainly to southern and western areas of the Big Island this week.
"Earthquake activity, ground deformation and continuing high emission rates of sulfur dioxide in the area indicate additional outbreaks of lava are likely as this eruption continues,"the Hawaiian Volcano Observatory reported late Saturday.
Several earthquakes up to magnitude 4.4 shook areas around the volcano on Wednesday as ground deformation continued.
"Employees at the Hawaiian Volcano Observatory, Hawai`i Volcanoes National Park and nearby residents are reporting frequent ground shaking and damage to roads and buildings,"the USGS said.
"Strong earthquakes in the area around Kilauea Volcano's summit are expected to continue and may become more frequent,"the USGS said.
Such fears prompted officials to close much of Hawaii Volcanoes National Park until further notice.
"Due to the ongoing seismic activity and the anticipated explosions caused by large rock falls, the interaction of ground water and lava and the possibility of an ensuing ashfall event, the Kīlauea portion of the park will be closed...until further notice,”National Park Service officials said in a statement.
Steam and gas rise from Kilauea's summit crater in Volcanoes National Park, Hawaii, Thursday, May 10, 2018. The park is closing Friday due to the threat of an explosive volcanic eruption. (AP Photo/Jae C. Hong)
The national park closed entirely on Friday, May 4, due to strong and damaging earthquakes. No injuries were reported and about 2,600 visitors were evacuated.
“A magnitude 6.9 earthquake struck at 12:32 p.m. Friday and caused violent shaking throughout the park. It triggered rockslides on park trails, crater walls and along sections of Chain of Craters Road,”officials said at the time.
"Just one hour earlier, a magnitude 5.4 earthquake caused a coastal cliff to collapse into the ocean near the Hōlei Sea Arch.”
Steam and gas rise along the edge of Kilauea's summit crater in Volcanoes National Park, Hawaii, Thursday, May 10, 2018. The park is closing Friday due to the threat of an explosive volcanic eruption. (AP Photo/Jae C. Hong)
It’s easy to see why #KilaueaVolcano is closing @Volcanoes_NPS beginning Friday. It’s very active with many steam and dust eruptions overnight. Officials are worried about a major steam driven eruption soon. @breakingweather @accuweather #accuphoto pic.twitter.com/DHgCx0kWEL— Jonathan Petramala (@jpetramala) May 10, 2018
Visitors watch as steam and gas rise from Kilauea's summit crater in Volcanoes National Park, Hawaii, Wednesday, May 9, 2018. (AP Photo/Jae C. Hong)
On Thursday, May 10, A USGS geologist inspects a crack that widened considerably in the past day on Old Kalapana Road in Leilani Estates. (Photo/U.S. Geological Survey)
In this photo taken from video an unidentified man gets close to a lava flow advancing down a road in the Leilani Estates subdivision near Pahoa on the island of Hawaii Monday, May 7, 2018. Kilauea volcano has destroyed more than two dozen homes since it began spewing lava hundreds of feet into the air last week, and residents who evacuated don't know how long they might be displaced. The decimated homes were in the Leilani Estates subdivision, where molten rock, toxic gas and steam have been bursting through openings in the ground created by the volcano. (Scott Wiggers/Apau Hawaii Tours via AP)
Short-lived plume of ash from Pu‘u ‘Ō‘ō captured during an HVO overflight. (Photo/USGS/Kevan Kamibayashi)