Report on Kilauea (United States) — 22 January-28 January 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 22 January-28 January 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, 22 January-28 January 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 20-27 January, lava continued to enter the ocean at the West Highcastle entry. Kilauea's summit began to deflate on 20 January at 1710, and Pu`u `O`o began to deflate a few tens of minutes later. Both areas deflated well into the next day. On the 21st at 1610 rapid, brief inflation began at the summit. The inflation and preceding deflation were centered near the NE corner of Halemaumau Crater, the normal center of small deformation events. Seismicity increased with the deformation events, returning to normal levels afterwards. Relatively large surface lava flows were visible starting on 21 January around 2035. By 22 January seismicity had returned to its normal level, with the long-lasting swarm of long-period earthquakes and tremor at Kilauea's summit, which began last June, continuing at weak-to-moderate levels.
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.