Report on Kilauea (United States) — 22 October-28 October 2008
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
22 October-28 October 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, 22 October-28 October 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 22-28 October lava flowed SE through a tube system from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex, reaching the Waikupanaha ocean entry. Lava flow production possibly paused during 26-27 October. Multiple surface lava flows on the pali were noted. On 23 October, a plume drifted above the County Viewing Area near the ocean entry and rained acid droplets, causing a closure. Explosions at the ocean entry were reported on 24 October. The sulfur dioxide emission rate at Pu'u 'O'o was 1,000 tonnes per day on 23 and 24 October, half of the background rate of the 2005-2007 average. Weak winds caused the viewing area to close again on 25 October.
During the reporting period, Kilauea earthquakes were variously located beneath and to the S of the caldera, along the S-flank faults, and along the SW rift zone. Beneath Halema'uma'u crater earthquakes ranged from less than 30 per day to 70 (background is about 40), but were too small to be located more precisely. The vent in Halema'uma'u crater continued to produce a predominantly white plume that drifted mainly SW. Night-time incandescence was intermittently seen at the base of the plume, and sounds resembling distant surf, rock clattering, and rock impacts were heard in the vicinity of the crater. Weak winds resulted in poor air quality at the summit during 21 and 25-28 October. During an overflight on 24 October, HVO geologists used a FLIR (Forward Looking InfraRed) camera to view the vent. The vent (about 80 m by 60 m) was wider than a lower orifice (about 30 m by 15 m), but narrower than a chamber above the orifice, resulting in an over-hanging vent rim prone to collapse. The sulfur dioxide emission rate was 500-900 tonnes per day during 22-24 October. The 2003-2007 rate average 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.