Report on Kilauea (United States) — 21 January-27 January 2004
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 21 January-27 January 2004
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2004. Report on Kilauea (United States). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 21 January-27 January 2004. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
On 22 January lava was emitted from the vent that formed at Kilauea on 19 January (the vent and lava flow S of Pu`u `O`o cone were named MLK in honor of the activity that began on Martin Luther King Jr.'s birthday). There were also surface lava flows at the W side of the Amalgamated Bend shield SW of Pu`u `O`o. By 26 January there were no surface lava flows at the MLK vent, and incandescence was only visible at the S part of the rootless shield complex. On 23 January moderate-to-strong tremor beneath Kilauea's caldera stopped, while it lessened at Pu`u `O`o. On 26 January deflation that began on 18 January ended at Pu`u `O`o after reaching 24.7 microradians. This was probably the largest deflation event since early 1997.
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.