Report on Kilauea (United States) — 15 February-21 February 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 15 February-21 February 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Kilauea (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 15 February-21 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 15-21 February, HVO reported that the lava lake circulated and periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Strong incandescence was visible from the collapsed cone on the NE edge and weaker from a cone on the SE edge during 15-18 and 20 February. A web camera recorded strong incandescence above the pali during 15-16 February. Incandescence also emanated from two sources on the E flank on 19 and 21 February.
Web camera views and satellite images indicated that lava flows remained active within the abandoned Royal Gardens subdivision more than 6.5 km SE of Pu'u 'O'o during 15-21 February. The flows advanced down the pali along the E side of the December 2011 flows during the week and on 21 February advanced to the kipuka on the E. On 17 February a second smaller branch appeared on the W side of the December 2011 flows. Ground-based observers reported active lava flows at the top of the pali during 15-21 February.
Geologic Background. Kilauea, which overlaps the E flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halemaumau crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 km2, destroying nearly 200 houses and adding new coastline to the island.