Report on Kilauea (United States) — 5 August-11 August 2009
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 5 August-11 August 2009
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2009. Report on Kilauea (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 5 August-11 August 2009. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
During 5-11 August, HVO reported that lava flowed SE from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex through a lava tube system, reaching the Waikupanaha ocean entry. Thermal anomalies detected in satellite images and visual observations revealed active surface flows on the pali, and along the E and W TEB flow field. The vent in Halema'uma'u crater continued to produce a diffuse white plume that drifted mainly SW. Small amounts of ash-sized "rock dust," likely generated from small vent wall collapses, were retrieved from collection bins placed near the plume. The sulfur dioxide emission rate at the summit remained elevated; 1,800 tonnes per day was measured on 7 August. The 2003-2007 average rate was 140 tonnes per day. For the first time in weeks, on 10 August, incandescence from the vent was seen.
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.