Report on Kilauea (United States) — 25 June-1 July 2008
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 25 June-1 July 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, 25 June-1 July 2008. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
Based on visual observations from HVO crews and web camera views, HVO reported that during 25 June-1 July, lava flowed SE through a lava tube system from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex to the Waikupanaha ocean entry. On 24 June, small episodic explosions at Waikupanaha propelled spatter about 50 m into the air; explosions were also noted on other days. The sulfur dioxide emission rate was 1,300 tonnes per day when measured on 24 June; the average background rate was about 2,000 tonnes per day. During 28 June-1 July, a small surface 'a'a lava flow near the E boundary of the Royal Gardens subdivision advanced E. During 30 June-1 July, several surface flows from multiple points along the lava tube system were noted.
During the reporting period, Kilauea summit earthquakes were located beneath the summit area, along S-flank faults, and along the E and SW rift zones. Another 20-60 small earthquakes per day also occurred but were too small to be located. The vent in Halema'uma'u crater continued to produce a white plume with minor ash content that drifted mainly SW. Night-time incandescence was seen at the base of the plume. Seismic tremor was elevated. The sulfur dioxide emission rate was 900 tonnes per day when measured on 26 June. The background rate is 150-200 tonnes per day.
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.