Report on Kilauea (United States) — 20 July-26 July 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 20 July-26 July 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on Kilauea (United States). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 20 July-26 July 2005. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
During 21-26 July, lava from Kilauea continued to enter the sea at the East Kamoamoa and East Lae`apuki entries. Small areas of surface lava were occasionally visible along the PKK lava flow. Background volcanic tremor was well above normal levels at Kilauea's summit and at moderate levels at Pu`u `O`o cone. An M 4.5 earthquake occurred on 25 July at 2208 along the SE edge of Kilauea's SW rift zone at a depth of ~30 km.
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.