Report on Kilauea (United States) — 26 September-2 October 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 26 September-2 October 2001
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2001. Report on Kilauea (United States). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 26 September-2 October 2001. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
Lava flows from the W of the active flow field began to enter the ocean at a new area during the evening of 28-29 September. The ocean entry was located S of the former site of Komoamoa camping area. By 30 September a new lava bench and an adjacent black sand beach had begun to form. Lava continued to flow into the ocean at the E Kupapa`u entry, although the overall size of the entry had diminished. Surface lava flows were visible above and on the Pulama pali scarp. The lava flows W and E of the flow field that had been active for the past couple of weeks had mostly crusted over. Generally, volcanic tremor remained at moderate-to-low levels at Kilauea's summit and Pu`u `O`o. Background tremor at Pu`u `O`o was interrupted at intervals of ten's of minutes to an hour or two, by short-lived bursts of relatively vigorous tremor. Tiltmeters across the volcano showed no significant deformation.
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.