Report on Kilauea (United States) — 31 December-6 January 2009
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
31 December-6 January 2009
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, 31 December-6 January 2009. 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 31 December-6 January lava flowed SE through a tube system from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex, reaching the Waikupanaha ocean entry. Surface flows were noted on the coastal plain and incandescence was seen at the base of the pali. Explosions at the ocean entry were seen on 31 December and 5 January.
Earthquakes strong enough to be located were variously scattered beneath the caldera, along the SW rift zone, and along the S-flank fault. The vent in Halema'uma'u crater continued to produce a predominantly white plume that drifted mainly SW. Consistent with a decreasing trend of ash production since 15 December, the vent produced minimal amounts of fine tephra; essentially no tephra was collected during 5-6 January. Sounds resembling rockfalls were sometimes heard in the vicinity of the crater. The sulfur dioxide emission rate at the summit was 500 tonnes per day on 31 December and 2 January; the 2003-2007 average rate was 140 tonnes per day.
Geological Summary. Kilauea overlaps the E flank of the massive Mauna Loa shield volcano in the island of Hawaii. Eruptions are prominent in Polynesian legends; written documentation since 1820 records frequent summit and flank lava flow eruptions interspersed with periods of long-term lava lake activity at Halemaumau crater in the summit caldera until 1924. The 3 x 5 km caldera was formed in several stages about 1,500 years ago and during the 18th century; eruptions have also originated from the lengthy East and Southwest rift zones, which extend to the ocean in both directions. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1,100 years old; 70% of the surface is younger than 600 years. The long-term eruption from the East rift zone between 1983 and 2018 produced lava flows covering more than 100 km2, destroyed hundreds of houses, and added new coastline.