Report on Kilauea (United States) — 27 August-2 September 2008
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 27 August-2 September 2008
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, 27 August-2 September 2008. 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 27 August-2 September, lava flowed SE through a lava tube system from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex and reached the Waikupanaha ocean entry. On 31 August, students from the University of Hawaii at Hilo reported low-level explosive activity at Waikupanaha.
A high number of Kilauea's earthquakes were centered in various locations along the Koa'e fault system, beneath the summit, N of Kupaianaha, along the S-flank faults, and along the E and SW rift zones. Beneath Halema'uma'u crater, more than 40 and up to 400 small earthquakes per day (background 40) also occurred but were too small to be located more precisely. The vent in Halema'uma'u crater continued to produce a predominantly white plume with minor ash content that drifted mainly SW. The plume was occasionally tinged brown. Weak night-time incandescence was intermittently seen at the base of the plume, and rock impacts and muted rushing sounds were heard in the vicinity of the crater. During 26-27 August, multiple ash ejections were observed. On 27 August, the white plume was temporarily tinged brown and rose to a higher altitude following an explosive eruption (the fifth in 2008). Glass fragments and tephra up to 5 cm in diameter burned holes in a collection tarp placed near the overlook. Analysis of photos captured over the previous month showed that the vent had lengthened by almost 50 percent along the edge of the crater floor. On 29 August, the collection bin contained Pele's hair, Pele's tears, and a variety of other shapes of glass fragments.
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.