Report on Kilauea (United States) — 21 May-27 May 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
21 May-27 May 2003
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, 21 May-27 May 2003. 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 May, surface lava flows were visible on Kilauea's coastal flat and the Pulama Pali fault scarp. Small amounts of lava began to flow into the sea on 21 May. Generally, seismicity was at normal levels, with little or no volcanic tremor occurring at Kilauea's summit. A swarm of small, low-frequency earthquakes occurred during 23 May until at least 26 May. The swarm occurred at shallow depths below the caldera floor and was the second such swarm in a 10-day period. No significant deformation occurred during the report period.
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.