Report on Kilauea (United States) — 22 February-28 February 2012
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 22 February-28 February 2012
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2012. Report on Kilauea (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 22 February-28 February 2012. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
During 22-28 February, HVO reported that the lava lake circulated and periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Web camera views and satellite images indicated that lava flows remained active within the abandoned Royal Gardens subdivision more than 7.5 km SE of Pu'u 'O'o. Lava flows also remained active high on the pali and across the December 2011 flows. Incandescence was visible on the NE and SE edges of the Pu'u 'O'o crater floor and on the upper part of the lava-tube system on Pu'u 'O'o's E flank during 23 and 26-28 February. On 22 February a small lava flow from the SE source was observed by the web camera. Two minor lava flows issued from the NE source on 26 February, and one lava flow issued from NE source on 27 February.
On 25 February HVO geologists aboard an overflight reported that the small cone on the NE source periodically ejected spatter, and the SE source fumed and produced a lava flow. They also noted that the flow advanced as two lobes; one lobe traveled along the E margin of the December 2011 flows and another advanced along the W margin of the December 2011 flows. During 27-28 February the web camera and satellite images indicated that both the E and W lobes continued moving down the pali.
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.