Report on Kilauea (United States) — 23 December-29 December 2009
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 23 December-29 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, 23 December-29 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 23-29 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. Thermal anomalies detected by satellite and visual observations revealed active lava flows on and at the base of the pali, and on the coastal plain. On 26 December, explosions at the ocean entry ejected material 15 m high. Incandescence was seen almost daily coming from Pu'u 'O'o crater. The vent in Halema'uma'u crater continued to produce a plume that drifted mainly SW, dropping small amounts of ash, and occasionally fresh spatter, downwind. Incandescence originated from a very active, sloshing lava surface within a single opening on the deep floor of the vent cavity. Parts of the opening rim periodically collapsed into the lava surface generating spatter that deposited on the floor and walls of the vent cavity.
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.