Report on Kilauea (United States) — 24 September-30 September 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 24 September-30 September 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, 24 September-30 September 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 23-30 September 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. Small collapses from the inner wall occasionally occurred and on 24 September produced a small brown plume from the vent. At Pu'u 'O'o Crater, glow emanated from several outgassing openings in the crater floor. Volcanologists on an overflight on 26 September observed sloshing lava in the pits.
The 27 June NE-trending lava flow remained active upslope from the leading edge. By 22 September the flow had extended 16.4 km from the vent (measured in a straight line), placing the active flow front within the NW portion of the Kaohe Homesteads, a vacant forested portion of the subdivision, 2.3 km upslope from Apa`a Street and 3.3 km from Pahoa Village Road. Two slow-moving lobes behind the flow front advanced; the nearest lobe was about 125 m behind the stalled front. During an overflight on 29 September volcanologists observed breakouts where the flow first entered the crack system about 8 km behind the stalled front, and where it exited the system about 3 km upslope from the front. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Warning.
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.