Report on Kilauea (United States) — 16 December-22 December 2009
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
16 December-22 December 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, 16 December-22 December 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 16-22 December, HVO reported that lava flowed SE from beneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex through a lava tube system, reaching the ocean at Waikupanaha. Incandescence was seen almost daily coming from Pu'u 'O'o crater. The vent in Halema'uma'u crater continued to produce an off-white plume that drifted E and SW, dropping small amounts of ash downwind. Incandescence originated from a few holes in the deep floor of the vent cavity. Occasionally, lava ponded on the floor of the cavity. Spatter originated from a small spatter cone on the E side of the vent cavity floor. Spatter from the opening frequently fed small lava flows that traveled down the flank of the cone. The sulfur dioxide emission rate at the summit remained elevated; 600 tonnes per day were measured on 18 December. The 2003-2007 average rate was 140 tonnes per day.
Geological Summary. 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.