VISIT THE ACTIVE ERUPTION SITE
Not much new happened in the first part of January. Lava continued to pour into the ocean, pretty much without any interruption. The bench that began growing after the December 2nd collapse is still growing, but hasnít gotten quite as big as the huge bench that formed this fall.
January 20th - we flew out again to check out the state of Pu'u O'o. There was a chunk of the knife ridge missing at the top, but otherwise all seemed pretty much the same.
Great excitement at the end of January! On the evening of 29 Jan. the instruments at HVO started detecting shallow earthquakes on the East rift zone and the summit of the volcano started deflating. Volcanologist Carl Thornber and seismologist Wil Tanigawa were the first on the scene, along with the new HVO Scientist-in-Charge, Don Swanson. They had soon called in National Park and Civil Defense authorities to discuss the possibility of a new outbreak.
At 3:00am, they were proved right as a fissure eruption burst out at Napau Crater (uprift from Pu'u O'o, closer to the summit). Geologists were on the scene as soon as possible to get samples and keep an eye on the activity, while Park rangers closed roads, evacuated campers and watched for burning trees.
At sunrise, geologists reported that the entire summit of Pu'u O'o had collapsed - an overflight showed that the lava lake, a fixture for over 10 years, was gone. In its place was a 1000 foot deep rubble-filled hole in the ground.
The fissures (it turned out there were 3 short en echelon fissures, labeled A, B, and C) died out by 7:30am and the first crew of exhausted geologists was relieved. The new flows were mapped out by GPS and the gas crew came out to sample new fuming cracks.
At 1:30 pm, Fissure C opened up again, spreading east for nearly 1 km beyond its original length. Fountains of lava jetted up 50 to 100 feet and lava poured into the pre-existing graben known as Steam Cracks. By 2:30pm the activity had almost died out at the western end, though the eastern end continued degassing and low fountaining for a little longer.
Video clip of fountains (260kb)
Several more short-lived fissure eruptions occurred: at 5pm Fissure E erupted out of Steam Cracks, a little further east of where lava had flowed in earlier, and at 9:00pm that night a new fissure cracked the wall of Napau Crater and poured lava onto the floor. The following day, some residual degassing and low fountaining was reported by vigilant geologists, but the tremor dropped, deflation stopped and eruptive activity ceased.