Report on Kilauea (United States) — 1 April-7 April 2009
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 1 April-7 April 2009
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2009. Report on Kilauea (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 1 April-7 April 2009. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
During 1-7 April, HVO reported that lava flowed SE from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex through a lava tube system, reaching the Waikupanaha and Kupapa'u ocean entries. Surface flows on the coastal plain were seen or detected by satellite imagery. Occasional explosions occurred from the Waikupanaha ocean entry. On 2 April, geologists found that the surface lava flow feeding the Kupapa'u entry was 1 km (0.6 m) wide.
The vent in Halema'uma'u crater continued to produce a predominantly white plume that drifted mainly SW. Incandescence was intermittently seen from the vent, and sounds resembling rushing gas were sometimes heard in the vicinity of the crater. Variable amounts of tephra including some Pele's hair, Pele's tears, and rock dust were retrieved daily from collection bins placed near the plume. During 31 March and 1 April, geologists utilizing an infrared camera to look into the vent saw a lava pond that rose and fell approximately every 3 minutes. During 2-3 April, the lava pond was replaced by a large hot opening; ejected spatter built up a rim. The sulfur dioxide emission rate at the summit was elevated; measurements were 550, 800, and 700 tonnes per day on 1, 2, and 3 April, respectively. The 2003-2007 average rate was 140 tonnes per day.
Geological Summary. Kilauea overlaps the E flank of the massive Mauna Loa shield volcano in the island of Hawaii. Eruptions are prominent in Polynesian legends; written documentation since 1820 records frequent summit and flank lava flow eruptions interspersed with periods of long-term lava lake activity at Halemaumau crater in the summit caldera until 1924. The 3 x 5 km caldera was formed in several stages about 1,500 years ago and during the 18th century; eruptions have also originated from the lengthy East and Southwest rift zones, which extend to the ocean in both directions. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1,100 years old; 70% of the surface is younger than 600 years. The long-term eruption from the East rift zone between 1983 and 2018 produced lava flows covering more than 100 km2, destroyed hundreds of houses, and added new coastline.