Report on Kilauea (United States) — 31 December-6 January 2004
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
31 December-6 January 2004
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Kilauea (United States). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 31 December-6 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)
During 30 December to 5 January, volcanic activity continued at Kilauea's Pu`u `O`o crater, but surface lava flows were not observed on Pulama pali or the coastal flat below Paliuli and no lava entered the ocean. During 30 and 31 December, much lava was emitted from vents on the W side of Pu`u `O`o's crater floor. Nearly the entire W part of the crater floor was covered by new lava flows. Above the Pulama pali fault scarp, SW of Pu`u `O`o, several active shields (a pile of lava flows built over a lava tube rather than over a conduit feeding magma) were seen in the upper rootless shield complex on 31 December and spatter cones were seen at the top of West Gap shield on 5 January. During the report period, few earthquakes occurred at Kilauea's summit and volcanic tremor at Pu`u `O`o continued at moderate levels. In addition, small amounts of inflation and deflation were recorded.
Geological Summary. 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.