Report on Kilauea (United States) — 20 April-26 April 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 20 April-26 April 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, 20 April-26 April 2011. 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 April, HVO reported that activity at Kilauea continued from the summit caldera and from Pu'u 'O'o crater. The level of the circulating lava-pool surface in a deep pit below the Halema'uma'u crater floor periodically fluctuated. A gas plume from the vent drifted mostly SW, and deposited very small amounts of ash nearby. At Pu'u 'O'o crater, central sources continuously erupted lava within a perched lava lake that was approximately half the diameter of the crater floor. The lava level fluctuated within the lake walls and episodically overflowed the rim. During 23-24 April lava from several central sources buried most of the perched lake and covered the crater floor. During 24-25 April several large draining events were characterized by a drop in the new lava-lake surface by several meters and minor collapses of the lake's rim.
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.