Report on Kilauea (United States) — 28 September-4 October 2011
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 28 September-4 October 2011
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2011. Report on Kilauea (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 28 September-4 October 2011. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
During 28 September-4 October, HVO reported that the lava lake circulated and periodically rose and fell in the deep pit within Kilauea's Halema'uma'u crater. Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and occasionally fresh spatter nearby.
At the E rift zone, the fissure that formed on 21 September on the upper E flank of Pu'u 'O'o continued to feed lava flows on 28 September that traveled along the edges of a low lava ridge. Most of the active lava spread out at higher elevations S and W of Pu'u Halulu (1.3 km NE of Pu'u 'O'o). Lava activity resumed from two sources on the E edge of the Pu'u 'O'o Crater floor and continued to spread W within the crater. During an overflight on 29 September, geologists observed that the fissure fed scattered active lava flows within 1.8 km on the SE flank of the cone. During 2-3 October lava from the E-crater floor source covered the crater floor. On 4 October active lava was confined to a small lake on the E side of the crater floor.
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.