Report on Kilauea (United States) — 22 August-28 August 2007
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 22 August-28 August 2007
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2007. Report on Kilauea (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 22 August-28 August 2007. 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 fissure segment D from Kilauea's 21 July fissure eruption continued to feed an advancing 'a'a lava flow during 22-28 August. In the last several weeks, four 'a'a flows had started from the open lava channel fed by Fissure D. From the second flow, each had advanced along the N edge of the previous one. The first two flows advanced a total of 6.3 km from the fissure source by 24 August. On 25 August, HVO geologists confirmed that the first three flows were inactive and the fourth flow had advanced 300 m and burned vegetation at the forest edge. During 25-26 August, the channel overflowed at a point about 1 km from the vent and spread along a section of the channel about 200-300 m long. During 27-28 August, the fourth flow was about 5.1 km from the vent and continued to advance.
Incandescence was visible on the web camera from E and W vents in Pu'u 'O'o's crater on 24 and 26 August. Small earthquakes were predominantly located beneath Halema'uma'u crater and the S flank during the reporting period.
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.