Report on Kilauea (United States) — 4 February-10 February 2009
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
4 February-10 February 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, 4 February-10 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 4-10 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 7 and 8 February, multiple explosions at the ocean entry were seen. On 9 February, booming noises and explosions were noted at the ocean entry; observers reported lava bubble bursts at 15-30 minute intervals. Seismicity and later observations indicated that the bench had collapsed. 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; the plume turned brown on 5 and 7 February. Small amounts of tephra were routinely collected. Incandescence was intermittently seen from the vent, and sounds resembling rushing gas and rockfalls were sometimes heard in the vicinity of the crater. Geologists looked into the vent on 4 and 6 February and saw lava rising and falling about 115-120 m below the vent rim. The sulfur dioxide emission rate at the summit was 900 tonnes per day on 4 and 9 February, and 500 tonnes on 5 February; 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.