Report on Kilauea (United States) — 2 April-8 April 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 2 April-8 April 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, 2 April-8 April 2003. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
Lava continued to enter the ocean at the West Highcastle entry at Kilauea during 1-8 April. Surface lava flows were visible on the Kohala lava flow and Pulama pali. During the beginning of the report period, lava traveled over the Chain of Craters Road. The lava cooled and ceased flowing over the road by the 3rd. Generally, seismicity remained at normal to below-normal levels. The summit swarm of long-period earthquakes and tremor, which began last June, was weak, with scattered earthquakes and sparse low-frequency tremor. Volcanic tremor at Pu`u `O`o was relatively high during the last few days of the report period. Small deformation changes occurred mostly at Pu`u `O`o.
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.