Report on Kilauea (United States) — 17 March-23 March 2004
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
17 March-23 March 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, 17 March-23 March 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 17-23 March, there were surface lava flows at the southern part of Kilauea's rootless-shield complex, which is along the Mother's Day lava tube S of Pu`u `O`o cone. A deflation-inflation-deflation event on 20 March culminated in lava emerging from the S base of Pu`u `O`o cone. No surface lava had been added to the crater floor over the previous couple of weeks. During the report period, very weak background tremor continued at Kilauea's summit along with brief periods of long-period earthquakes. Volcanic tremor at Pu`u `O`o remained at moderate levels.
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.