During 4 February-5 March, the Pu`u `O`o eruption returned to steady-state activity after a brief magma surge and two seismic swarms in January (BGVN 22:12 and 23:01). Seismicity was low and little inflation or deflation was detected at Kīlauea's summit. Magma moved through shallow conduits towards the E rift zone without disturbing the ground surface.

The Pu`u `O`o vent area remained relatively unchanged in appearance during February. Fumes issued from cracks in the cone and surrounding area. Profuse fumes from new cracks near the N rim obscured the views of remote surveillance cameras and observers on helicopter overflights.

Lava continued to travel in tubes from the Pu`u `O`o vents to the ocean; however, during 4-24 February surface lava flows were sparse. Every 4-5 days a small flow issued from the lava tubes across the coastal plain. Most of the surface flows were near the Waha`ula ocean entry. At Kamokuna, lava continued to form a low shelf or bench at the foot of a 10-15 m cliff bordering the ocean. A bench collapse at the Kamokuna coastal entry occurred between 16 and 19 February. The collapse destroyed 4 hectares of land that had formed since the most recent collapse on 15 January (BGVN 22:12). The lava supply to the coastal tube system was interrupted briefly on 21 February, causing the steam plumes at the sea entry to dwindle for most of the day.

Kīlauea is one of five coalescing volcanoes that comprise the island of Hawaii. Historically its eruptions originated primarily from the summit caldera or along one of the lengthy E and SW rift zones that extend from the summit caldera to the sea. This latest Kīlauea eruption began in January 1983 along the E rift zone. The eruption's early phases, or episodes, occurred along a portion of the rift zone that extends from Napau Crater on the uprift end to ~8 km E on the downrift end. Activity eventually centered on what was later named Pu`u `O`o. More than 223 hectares of new land have been added to the island and local communities have suffered more than $100 million in damages since the beginning of the eruption.

Geological Summary. Kilauea overlaps the E flank of the massive Mauna Loa shield volcano in the island of Hawaii. Eruptions are prominent in Polynesian legends; written documentation since 1820 records frequent summit and flank lava flow eruptions interspersed with periods of long-term lava lake activity at Halemaumau crater in the summit caldera until 1924. The 3 x 5 km caldera was formed in several stages about 1,500 years ago and during the 18th century; eruptions have also originated from the lengthy East and Southwest rift zones, which extend to the ocean in both directions. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1,100 years old; 70% of the surface is younger than 600 years. The long-term eruption from the East rift zone between 1983 and 2018 produced lava flows covering more than 100 km2, destroyed hundreds of houses, and added new coastline.

Information Contacts: Hawaiian Volcano Observatory (HVO), U.S. Geological Survey, PO Box 51, Hawaii Volcanoes National Park, HI 96718, USA (URL: https://volcanoes.usgs.gov/observatories/hvo/); Ken Rubin and Mike Garcia, Hawaii Center for Volcanology, University of Hawaii, Dept. of Geology & Geophysics, 2525 Correa Rd., Honolulu, HI 96822 USA (URL: http://www.soest.hawaii.edu/GG/hcv.html).