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Report on Kilauea (United States) — May 1987


Kilauea

Scientific Event Alert Network Bulletin, vol. 12, no. 5 (May 1987)
Managing Editor: Lindsay McClelland.

Kilauea (United States) Lava enters ocean from underwater tubes and surface flows

Please cite this report as:

Global Volcanism Program, 1987. Report on Kilauea (United States) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 12:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198705-332010



Kilauea

United States

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

All times are local (unless otherwise noted)


The primary activity . . . in May and early June was a slow advance of dense pahoehoe continually overriding older flows. By mid-May the lava . . . was completely within tubes, with some minor breakouts . . . at 150-20 m elevation late in the month. Low-volume lava flows entered the ocean 11-18 May. On 17 May, divers reported lava issuing from tube openings ~10 m underwater. Occasional lava extrusions along the tube system fed flows that overran > 30 m of Hwy 130 on 29 May and 2 June, buried more of Pacific Paradise Ocean Front Estates (partially overrun in November 1986) and again entered the ocean on 4 June. More than 1.8 km of the Chain of Craters Road has been covered with lava.

The level of the lava pond over the vent at 670 m elevation varied from as much as 9 m below the rim to vigorous overflows on 30 May. Tumescence followed by intermittent breakouts of pahoehoe and aa occurred in the shield's N flank, forming short flows.

The summit tiltmeter showed minor fluctuations but indicated no long-term trend of inflation or deflation. Harmonic tremor persisted . . . near the eruptive vent. Bursts of relatively high-amplitude tremor lasting 5-20 minutes occurred at irregular intervals of less than an hour to many hours during the week of 6-13 May and again in early June. The number of microearthquakes was slightly above average in the summit and East rift zone. Earthquakes of M 2.5-3.5 were concentrated on the S flank of Kīlauea and the Kaoiki fault region at 5-10 km depth.

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.

Information Contacts: C. Heliker and R. Koyanagi, HVO.