Report on Kilauea (United States) — June 2004
Bulletin of the Global Volcanism Network, vol. 29, no. 6 (June 2004)
Managing Editor: Richard Wunderman.
Kilauea (United States) Surface lava flows and renewed ocean entries; lava tubes in June
Please cite this report as:
Global Volcanism Program, 2004. Report on Kilauea (United States) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 29:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200406-332010.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
During mid-2004 lava flows erupting from Kilauea once again began reaching the ocean, where they slowly added new land to the SE coast of Hawai`i Island (figure 164). Lava began spilling into the ocean on 30-31 May 2004. Nearly a year before that, on 9 July 2003, the lava tube system feeding flows to the ocean ceased carrying lava, which instead escaped in a series of breakouts and numerous surface flows between the Pu`u `O`o vent and the coast. Hundreds of breakouts occurred between July 2003 and May 2004 within ~ 5 km of the vent.
One of these flows, termed the Banana flow (see figure 164), started to advance down Pulama pali in April 2004. The Banana flow developed from breakouts from part of the Mother's Day lava tube, centered near the former Banana Tree kipuka (an "island" of undisturbed land completely surrounded by one or more lava flows). The breakouts became prominent in the middle of April, and lava started down Pulama pali shortly thereafter. The Banana Flow eventually reached the coastal flat on 2 May. It took nearly a month for the Banana flow to creep across the flat and enter the sea off Wilipe`a lava delta on 30 May. Interaction of the lava and water was not explosive. A spectacular set of photos of lava pouring into the ocean at this time appears on the Hawaiian Volcano Observatory website (figure 165, for example).
On 13 June, two collapses occurred at Kilauea's lava delta along its W sector, sending sizable chunks of the delta into the sea (figure 166). On 14 June, most lava was being supplied to the ocean through lava tubes, but several surface lava flows were visible on the delta and traveling down the old sea cliff behind the Wilipe`a delta. The larger eastern part of the lava delta had several active lava entries into the ocean, in general larger than those on the western part of the delta. All vents were active in the crater of Pu`u `O`o.
Since March 2004, very weak background tremor continued at Kilauea's summit along with a few long-period earthquakes. Tremor at Pu`u `O`o remained at its typical moderate levels through early June 2004, after which some higher levels were observed. Several episodes of inflation and deflation occurred during this time. One deflation-inflation event began 20 March and culminated 23 March with lava emerging from the S base of Pu`u `O`o cone. A weak swarm of low-frequency earthquakes and a 2-hour period of moderate-to-strong volcano tectonic earthquakes were recorded during 24-25 March.
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 (HVO), U.S. Geological Survey, PO Box 51, Hawaii National Park, HI 96718, USA (URL: https://volcanoes.usgs.gov/observatories/hvo/).