Report on Kilauea (United States) — 7 September-13 September 2011
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 7 September-13 September 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, 7 September-13 September 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 31 August-6 September, HVO reported that the level of the lava-lake surface in the deep pit within Kilauea's Halema'uma'u crater periodically fluctuated and circulated. Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and occasionally fresh spatter nearby. At Pu'u 'O'o' crater, lava from E, W, and S-central sources on the crater floor fed an eastern and a western perched lava lake during 7-8 September. Lava also covered much of the crater floor, rising to within 5 m of a low point on the E crater rim. During 9-10 September a large amount of lava from a new source of effusion at the NE edge of the crater covered most of the crater floor. On 10 September a pilot confirmed that lava overtopped the E rim and fed a short lava flow. Not long after that the effusion rate decreased and lava fed only the two perched lava lakes. During 11-13 September the lava lakes mostly circulated and, by 12 September, had overflowed onto 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.