Report on Kilauea (United States) — March 1980
Scientific Event Alert Network Bulletin, vol. 5, no. 3 (March 1980)
Managing Editor: David Squires.
Kilauea (United States) Two intrusions into the upper east rift
Please cite this report as:
Global Volcanism Program, 1980. Report on Kilauea (United States) (Squires, D., ed.). Scientific Event Alert Network Bulletin, 5:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198003-332010.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
Magma was intruded into the upper E rift zone on two occasions in March. On 2 March, a microearthquake swarm began near Pauahi Crater, 6 km downrift from the summit and site of a brief eruption in November 1979. Summit deflation, indicating draining of the magma chamber below, started within 7 minutes and a tiltmeter began to record deformation as magma was intruded downrift. About 2,000 earthquakes, including several felt events, were recorded before the swarm ended 8 hours later. Summit deflation, totaling only 8 mm, continued for another hour. Just over a week later, a second intrusion took place a few kilometers farther down the E rift beneath Mauna Ulu, active 1969-1974. Earthquakes began on 10 March at 2157, summit deflation at 2206, and volcanic tremor at 2310. Eight centimeters of deflation, representing the draining of 8 x 106 m3 of magma from the summit chamber, occurred before the end of summit deformation on 12 March at 1630. Volcanic tremor around Mauna Ulu waned slowly and had almost ceased by 13 March.
Inflation has resumed since the second intrusion. As of 2 April, the level of the summit was slightly higher than immediately prior to the November eruption.
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.
Information Contacts: Hawaiian Volcano Observatory, USGS.