Report on Kilauea (United States) — 6 August-12 August 2008
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 6 August-12 August 2008
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2008. Report on Kilauea (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 6 August-12 August 2008. 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 during 6 and 9-12 August lava flowed SE through a lava tube system from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex to the Waikupanaha ocean entry. Occasional explosions and surface lava flows were noted near the ocean entry. A small fountain in a lava pond at the top of one of the rootless shields was observed on 10 August. The sulfur dioxide emission rate at Pu'u 'O'o was 1,700 and 2,400 tonnes per day on 8 and 9 August, respectively; the average background rate is about 2,000 tonnes per day.
During the reporting period, Kilauea earthquakes were variously located beneath Halema'uma'u crater, along the Koa'e fault system, SE and W of the caldera, along the S-flank faults, and along the E and SW rift zones. Beneath Halema'uma'u crater, up to 100 small earthquakes per day (background is 20-40) also occurred but were too small to be located more precisely. The vent in Halema'uma'u crater continued to produce a mainly white plume with minor ash content that drifted SW. The plume was occasionally tinged brown. Night-time incandescence was seen at the base of the plume rock-clattering sounds were heard in the vicinity of the crater. The sulfur dioxide emission rate was high at 900 tonnes per day on 7 August. The pre-2008 background rate was 150-200 tonnes per day.
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.