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Report on Kilauea (United States) — 25 September-1 October 2002


Kilauea

Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
25 September-1 October 2002
Managing Editor: Gari Mayberry

Please cite this report as:

Global Volcanism Program, 2002. Report on Kilauea (United States). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 25 September-1 October 2002. Smithsonian Institution and US Geological Survey.

Weekly Report (25 September-1 October 2002)

Kilauea

United States

19.421°N, 155.287°W; summit elev. 1222 m

All times are local (unless otherwise noted)


During 25-30 September at Kilauea, lava continued to travel SE down Paliuli and Pulama pali, and surface lava flows were visible on the coastal flat. Lava entered the sea at multiple points along the fronts of two lava deltas and visitors saw several sudden collapses of the front of the bench (land built out from the sea cliff). Generally, seismicity was at normal levels. The swarm of long-period earthquakes and tremor beneath Kilauea's caldera that originally began in June was fairly weak. Periods of small deflation and inflation occurred at Uwekahuna and Pu`u `O`o tiltmeters, but no significant deformation was recorded elsewhere.

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.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)