Report on Kilauea (United States) — 30 September-6 October 2009
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 30 September-6 October 2009
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2009. Report on Kilauea (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 30 September-6 October 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 30 September-6 October, 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 revealed active surface lava flows on top of the pali. The vent in Halema'uma'u crater continued to produce a diffuse white plume that drifted SW. Small amounts of occasional fresh ash were retrieved from collection bins placed near the plume. During 30 September and 2, 4, and 5 October, a lava pond within the vent, about 200 m below the Halema'uma'u crater floor, rose and fell, circulated, and weakly spattered. Preliminary measurements indicated that the sulfur dioxide emission rate at the summit remained elevated; 410, 650, and 480 tonnes per day were measured on 30 September, 1 and 2 October, respectively. The 2003-2007 average rate 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.