Report on Kilauea (United States) — 27 July-2 August 2011
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 27 July-2 August 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, 27 July-2 August 2011. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
HVO reported that two lava lakes at Kilauea were active during 27 July-2 August. The level of the summit lava lake fluctuated deep in the 150-m-diameter vent inset within the E wall of Halema'uma'u Crater and circulated with various patterns. Periodic measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and occasionally fresh spatter nearby.
Lava from the Puka Nui and MLK pits, smaller craters to the W of the main Pu'u 'O'o crater, continued to overflow to the SW, producing a tube-fed pahoehoe flow that had advanced about 700 m from the Puka Nui rim during 25-30 July. Lava from the base of the NE crater filled a trough between the crater wall and the perched lava lake. Uplift of the crater floor and lava lake continued until 30 July, when a breakout lava flow started along the base of the crater's S wall and the lake slowly subsided. Subsidence continued the next day but switched to inflation on 1 August. The preliminary sulfur dioxide emission rate from all east rift zone sources was calculated at 1,700, 1,000, and 800 tonnes/day on 29 and 30 July, and 1 August, respectively.
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.