Report on Kilauea (United States) — 5 December-11 December 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
5 December-11 December 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, 5 December-11 December 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 continued flowing into the ocean at the Kamoamoa and E Kupapa`u ocean entries, and surface lava flows were visible at spots along the Kamoamoa lava tube system. Volcanic tremor was at low-to-moderate levels at Pu`u `O`o and low at Kilauea's summit, with weak long-period earthquakes occurring frequently. On 8 December rapid deflation (~2.4 microradians) occurred at Kilauea's summit, followed shortly thereafter by deflation (~1.9 microradians) at Pu`u `O`o cone. On 9 December abrupt inflation at Kilauea's summit (>6 microradians) was followed by much slower and lesser inflation at Pu`u `O`o. Strong earthquakes and tremor accompanied the inflation. A shallow M 3.4 earthquake was registered in the SE part of the caldera. By 10 December, seismicity had returned to normal levels at the summit, and tremor at Pu`u `O`o remained at a moderate level.
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.