Report on Kilauea (United States) — 20 August-26 August 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 20 August-26 August 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Kilauea (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 20 August-26 August 2014. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
During 20-26 August HVO reported that the circulating lava lake occasionally rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Gas emissions remained elevated. The plume from the vent continued to deposit variable amounts of ash, spatter, and Pele's hair onto nearby areas; smaller particles may have been dropped several kilometers away. On 23 August part of the deep inner ledge surrounding the lava lake collapsed, disrupting the lava lake surface for a short time.
During 20-26 August glow was visible overnight above several outgassing openings in Pu`u `O`o's crater floor and on 20-21 August glow was visible at skylights along the June 27th flow lava tube. On 22 August observations during a helicopter flight showed the June 27th flow had poured into a deep, large crack of Kilauea’s east rift zone and produced a line of steaming that advanced eastward. On 25 August an overflight confirmed that lava in the crack had returned to the surface, creating a small, isolated pad of lava. On 26 August the farthest portion of this new pad of lava was about 11.4 km from the vent on Pu`u `O`o and about 3.1 km from the eastern boundary of the Wao Kele o Puna Forest Reserve. A separate branch of the June 27th flow continued to advance into a different section of forest northeast of Pu`u `O`o and was 7.3 km from the vent on 25 August.
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.