Report on Kilauea (United States) — 25 May-31 May 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 25 May-31 May 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, 25 May-31 May 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 two lava lakes at Kilauea were active during 25-31 May. The level of the summit lava lake remained mostly stable deep in the vent inset within the E wall of Halema'uma'u Crater. An increase in the lake level covered the vent on the south side wall during 25-28 May. On other days lava from the vent cascaded down into the lake. A gas plume from the vent drifted SW. The (preliminary) sulfur dioxide emission rate from all east rift zone sources was 700 tonnes/day on 26 May; the emission rates were slowly increasing.
Lava from a vent near the W edge of the perched lava lake in the center of Pu'u 'O'o crater floor continued to fill the lake. The lake level fluctuated and occasionally overflowed the edges or flowed through rim breaches, sending lava onto the Pu'u 'O'o crater floor. The rim of the perched lava lake was elevated 10 m higher than the surrounding crater floor, which was 52 m below the E crater rim on 11 May. During 27-29 May lava from a vent at the base of the SW wall produced lava flows that slowly began filling the gap between the crater wall and the perched lake wall.
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.