Report on Kilauea (United States) — 17 October-23 October 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 17 October-23 October 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Kilauea (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 17 October-23 October 2012. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
During 17-23 October HVO reported that the circulating lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Occasional measurements indicated that the gas plume from the vent continued to deposit variable amounts of spatter and Pele's hair onto nearby areas. Cracking noises, audible from the Jaggar overlook and caused by rocks of the vent wall fracturing from the heat, emanated sporadically from the vent. On 18 October the lake rose to a level 42 m below Halema'uma'u Crater floor, and the next day the lake rose to 38 m below the floor. During 21-23 October the lake rose to within 33 m of the crater floor. Small collapses of rock into the N portion of the lava lake triggered small spatter explosions on 21 and 23 October.
Lava flows accumulated at the base of the pali in the Royal Gardens subdivision and flowed across the coastal plain, but were 1.4 km from the coast. Flows also remained active on the pali. At Pu'u 'O'o Crater, incandescence was visible from lava flows in the S pit, lava circulating in the NE pit, and from the W edge of the crusted N pit. Three small lava flows erupted from a spatter cone on the S side of the crater floor on 17 October. Two fuming hot vents in the same area were observed the next day. Activity at Pu'u 'O'o Crater was elevated during18-21 October; the lava lake in the NE pit overflowed its rim, the S pit produced three lava flows, and the spatter cone vigorously spattered.
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.