Report on Kilauea (United States) — October 1988
Scientific Event Alert Network Bulletin, vol. 13, no. 10 (October 1988)
Managing Editor: Lindsay McClelland.
Kilauea (United States) Repeated collapse of new coastal lava benches
Please cite this report as:
Global Volcanism Program, 1988. Report on Kilauea (United States) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 13:10. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198810-332010.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
. . . lava continued to flow into the ocean from the tube system near Kupapau Point through October. Some minor surface activity occurred 2-4 October when lava broke out from the tube system between 300 and 180 m elevation.
The coastal lava bench growth and collapse sequences continued. A major collapse on the 13th removed ~2/3 of the 220 x 30-40 m bench, and there were minor collapses on 20 and 29 October and 5 November. Benches collapsed suddenly, without warning, making viewing the coastal area very hazardous. Small littoral cones formed periodically, the largest 10 m high. They were soon stranded behind the growing shoreline, then destroyed as the benches collapsed. Pyroclastic material consisting of fine shards and Pele's hair was ejected by littoral explosions, forming a tephra blanket several centimeters thick > 250 m downwind.
The lava pond at Kupaianaha remained 15-28 m below the rim. A 5-m-diameter "island" was visible 15-24 October ~20 m from the pond's edge, probably a piece that had collapsed from the rim. Activity increased in Pu`u `O`o crater on 26-27 October, with lava covering ~25% of the crater floor. Lava appeared to well up through one of the two active vents on the crater floor, and drain back down the other.
Low-level tremor continued . . . near Pu`u `O`o, Kupaianaha, and the Wahaula station near the coastal lava flows. East-rift tremor showed steady amplitude until the 27th, then changed to a pattern of varying amplitude that produced a banded pattern on the revolving drum seismic recorders. High-amplitude tremor lasting < 1 hour typically alternated with several hours of low-amplitude tremor. The fluctuating tremor continued until 4 November, then resumed its typical steady pattern. Bursts of deep tremor . . . increased from last month. The number of microearthquakes was about average in the summit region and East rift zone. There were 12 earthquakes of M 2.6-4.1, mostly centered beneath Kilauea and Mauna Loa.
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: C. Heliker and R. Koyanagi, HVO.