Volcano Watch — Ten-year-long eruption resumes after short lull

The 10-year-long eruption at Kīlauea Volcano started up again during the morning of February 16, after a period of inactivity lasting about 10 days. The eruption began at the episode 51 vents on the west flank of Pu`u `O`o, with only small volumes of pasty lava flowing through the pre-existing tubes. 

By the afternoon of February 18, lava had advanced to the 1,900-foot level, where sluggish pahoehoe flows broke out of the tube system. By the morning of February 20, these flows had advanced to between the 300- and 500-foot elevation on the pali; their volume was still very small.

However, in the early afternoon of February 20, a new eruptive fissure opened up on the south side of Pu`u `O`o adjacent to the episode 52 vents. We have called this new vent the episode 53 vent. On Saturday, this new vent had small lava fountains, about 2-3 meters high. A small flow from this new vent headed south. The lava flows within the tube system below the episode 51 vents continued at small volume, so at this time, two vents were erupting side-by-side: the crusted-over episode 51 vent and the new episode 53 vent. 

About 1:00 a.m. on Sunday morning, February 21, the tremor recorded at our seismic station nearest Pu`u `O`o increased dramatically in amplitude. This increase suggested that the eruption had quickly become more vigorous and its volume, greater. Observations made the next morning revealed that the fountains at the new episode 53 vent had increased in vigor and were now about 15 meters high. The lava was ponding to the south of the vent. The flows along the pali that were erupted from the adjacent episode 51 vent were also still active. The glow for the next few nights was very strong because of the eruption and active lava pond at the episode 53 vent.

By Monday, the lava pond from the episode 53 vent had overtopped a skylight in the tube system below the episode 51 vent, and the lava from the episode 53 vent was draining into the pre-existing tube and moving underground to the top of the pali. It was no longer possible to visually determine whether the episode 51 vents were still active, as lava from the two vents was now commingled in the tube. At the top of the pali, the flow broke out of the tube and quickly advanced, as `a`a flows, over the pali. By the next day, the flows were two-thirds of the way to the base of the pali. 

By last Friday, the largest of these new flows had advanced to Paliuli above Kamoamoa and had begun to cascade over the pali just east of the flows that buried Kamoamoa between November and early February. Another, larger flow is also advancing down the main pali on the east side - and a smaller flow is advancing on the west side - of the earlier Kamoamoa flows. These flows should reach the ocean within a matter of days. They will probably flow over the earlier flows at Kamoamoa, or just to the east of those flows. The active surface lava flows are visible from the end of Chain of Craters Road in Hawai`i Volcanoes National Park.

A small lava lake once again occupies Pu`u `O`o Crater. The lava lake is about 215 feet below the rim, and overflows from the pond have coated the floor of the crater with new lava.