Report on Kilauea (United States) — 16 May-22 May 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 May-22 May 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, 16 May-22 May 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 16-22 May HVO reported that the circulating and spattering lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater, and spilled over the deep inner ledge on multiple occasions. On 15 May laser measurements indicated that the lava-lake surface was about 65 m below the Halema'uma'u Crater floor, among the highest levels measured; the lake rose five more meters during 18-19 May. Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash, and occasionally fresh spatter from the margins of the lava lake, onto nearby areas. A lava pond in a small pit on the E edge of Pu'u 'O'o crater floor remained active with spattering. On 19 May a small collapse of the N rim of the pit slightly enlarged the pit and lava pond within. A small lava flow erupted from a vent on the S part of the floor. Lava flows were active on the pali and the coastal plain, and were about 750 m from the sea.
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.