Report on Kilauea (United States) — 6 July-12 July 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 6 July-12 July 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, 6 July-12 July 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 6-12 July. The level of the summit lava lake fluctuated deep in the vent inset within the E wall of Halema'uma'u Crater and circulated with various patterns. Spattering occurred at locations along the W edge of the lake. Periodic measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash nearby. At Pu'u 'O'o, lava from vents near the NE edge and, to a lesser degree, along the W edge of the perched lava lake in the center of the crater floor continued to fill the lake. The lake level fluctuated and flowed through rim breaches, sending lava onto the Pu'u 'O'o crater floor. The near-vertical rim of the perched pond, which was elevated about 5 m higher than the surrounding sub-horizontal crater floor on the E side, continued to be uplifted; the crater floor and perched lake rims formed a nearly-continuous ramp sloping away from the lake.
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.