Report on Kilauea (United States) — 11 February-17 February 2009
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 11 February-17 February 2009
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2009. Report on Kilauea (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 11 February-17 February 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 11-17 February lava flowed SE from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex through a lava tube system, reaching the Waikupanaha and Waha'ula ocean entries. On most days, multiple explosions and spatter at the ocean entry were seen. On 11 February, geologists found a new littoral cone, on the edge of the bench, with a large crack running through it. Spatter on the cone and the bench behind it resulted from lava bubble bursts and steam jetting reported during the previous two days. A second crack between the cone and the sea cliff was also noted. The cracks suggested that the bench was slowly failing and did not collapse as reported a few days prior. Occasional incandescence originated from the Prince lobe, the flow that feeds the Waha'ula ocean entry. Thermal anomalies suggesting surface flows were noted on the coastal plain and on the pali.
The vent in Halema'uma'u crater continued to produce a predominantly white plume that drifted mainly SW; incandescence was intermittently seen from the vent. Small amounts of tephra, including Pele's hair and some spatter, were routinely collected. Infrared images taken during an overflight on 11 February revealed the development of a small spattering cone over the conduit that hosted a lava pond the previous week. Images taken on 14 February indicated that the conduit had mostly crusted over; a small, puffing vent was visible. The sulfur dioxide emission rate at the summit was 800 tonnes per day on 12 February, and 500 tonnes on 13 February; 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.