Report on Kilauea (United States) — 15 October-21 October 2008
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 15 October-21 October 2008
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2008. Report on Kilauea (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 15 October-21 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 15-21 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. Multiple surface lava flows on the pali were noted; on 16 October a channelized 'a'a flow was active in the Royal Gardens subdivision and a pahoehoe flow was seen on the W side of the active flow field. Lava destroyed one of two remaining intermittently occupied structures in the subdivision. The sulfur dioxide emission rate at Pu'u 'O'o was 1,000 tonnes per day on 17 October, half of the background rate of the 2005-2007 average. Explosions at the ocean entry were reported on 19 October.
During the reporting period, Kilauea earthquakes were variously located beneath and to the S of the caldera, and along the S-flank faults. Beneath Halema'uma'u crater earthquakes ranged from 40 per day to more than 100 (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, which was occasionally tinged brown in association with small local earthquakes or vent rim collapses, that drifted mainly SW. Night-time incandescence was intermittently seen at the base of the plume. Two vent explosions occurred on 14 October. The first was initiated by the collapse of a thin piece of the vent rim. The second explosion ejected molten spatter that fell within 100 m of the vent and produced an eruption plume that rose 2 km above the caldera rim. The sulfur dioxide emission rate was 600 and 900 tonnes per day on 16 and 17 October, respectively. The 2003-2007 rate average 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.