Report on Kilauea (United States) — 1 October-7 October 2008
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 1 October-7 October 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, 1 October-7 October 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 1-7 October lava flowed SE through a tube system from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex. Lava that reached the ocean entry generated a steam plume during much of the reporting period; a plume was absent during 4-6 October. The sulfur dioxide emission rate at Pu'u 'O'o was 1,400 tonnes per day on 5 October, below the background rate as averaged over the past 25+ years.
During the reporting period, Kilauea earthquakes were variously located beneath and to the S of the caldera, along the S-flank faults, and along the SW rift zone. Beneath Halema'uma'u crater small earthquakes per day ranged from less than 40 to 100 (background is about 20-40), but were too small to be located more precisely. The vent in Halema'uma'u crater continued to produce a predominantly white plume with occasional minor ash content that drifted mainly SW, but also in multiple other directions. Weak night-time incandescence was intermittently seen at the base of the plume. The sulfur dioxide emission rate was 900 and 1,100 tonnes per day on 3 and 5 October, respectively. The 2003-2007 rate average was 140 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.