Report on Kilauea (United States) — 19 January-25 January 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 19 January-25 January 2011
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2011. Report on Kilauea (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 19 January-25 January 2011. 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 the largest of about 36 rockfalls that occurred in the deep pit within Kilauea's Halema'uma'u crater on 17 January was followed by an explosive event, of a magnitude not seen since 2008, and felt locally. Ballistics up to 10 cm in diameter and hot tephra ejected from the pit were deposited on the rim of Halema'uma'u crater. Spatter up to 8 cm long was ejected onto the crater rim after collapses on 21 January.
During 19-25 January, activity continued from the summit caldera and the east rift zone. At the summit caldera, the level of the lava-pool surface in the deep pit within Halema'uma'u crater circulated and remained mostly stable at approximately 120 m below the crater floor, periodically rising or falling. Nighttime incandescence was visible from the Jaggar Museum on the NW caldera rim. A plume from the vent that drifted mostly SW and W deposited ash and fresh spatter nearby.
At the east rift zone, lava that broke out of the Quarry tube, at a saddle between two rootless shields around 610 m elevation, continued to advance both E and W. At the lowest elevation of the E branch, lava advanced along Highway 130 near Kalapana, periodically burning vegetation. Steam sporadically rising near the ocean suggested that the lava entered the ocean, although not continuously. One part of the W branch stopped entering the ocean on 18 January, but remained active. Incandescence emanated from a spatter cone on the N portion of the Pu'u 'O'o crater floor and from the fuming vent in the E wall of the crater.
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.