Report on Kilauea (United States) — 18 July-24 July 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
18 July-24 July 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, 18 July-24 July 2001. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
During the week lava entered the sea at a moderate rate at the E Kupapa`u entry. On 18 July at 1803 a M 3.5 earthquake rattled though the lower east rift zone of Kilauea. Surface flows were vigorous in two areas of the current lava flow field; one in the E branch of the flow field at the base of the Pulama pali scarp, and the other just SE of the shatter ring in the W branch of the flow field. Generally, weak, steady tremor and a few related long-period earthquakes continued beneath Kilauea's caldera. Near Pu`u `O`o, the tremor alternated from weak, to moderate, to strong over periods of several hours. Elsewhere, seismicity was at normal levels. Tiltmeters in the summit area and along the east rift zone indicated no significant deformation.
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.