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Report on Kilauea (United States) — December 1994


Kilauea

Bulletin of the Global Volcanism Network, vol. 19, no. 12 (December 1994)
Managing Editor: Richard Wunderman.

Kilauea (United States) Lava-flow breakouts cover new land and reach the ocean

Please cite this report as:

Global Volcanism Program, 1994. Report on Kilauea (United States) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 19:12. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199412-332010



Kilauea

United States

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

All times are local (unless otherwise noted)


Following a short pause . . ., lava flows broke out on 26 October and entered the ocean on 4 November in the same location as the previous Laeapuki entries. These flows quickly formed a tube system with many skylights and fluid pahoehoe breakouts active from the top of Pulama pali to the ocean. Lava flows extended to the W margin of the flow field, covering new land and burning more of Chain of Craters road. Flows were soon at the same level as the former sea cliff W of the eruption site. Lava entered the ocean across a broad front, but by 15 November the flow began to consolidate. On 23 November, flows active along the W side of the flow field were entering the ocean in the Laeapuki area. On the 25th, lava entry into the ocean slowed, eventually stopping altogether, coincident with a breakout on Pulama pali. Many flows were active on and above Paliuli during 25-28 November, but not on the coastal plain. On the 29th, a flow cascaded over Paliuli and advanced almost 300 m towards the ocean. The eruption paused the same day; this was the 6th pause since the beginning of 1994. By 30 November there were no active flows on the coastal plain, and only minor surface breakouts above Paliuli. The skylights were noticeably cooler and the flow in the tubes was low and sluggish. Pasty breakouts continued from the W side of the flow field as the system drained. At the end of November, a collapse pit on the W flank of Pu`u `O`o, immediately upslope of the E-51 vent, grew to ~80 m in diameter (4-5 times its former size).

On the morning of 1 December, no active surface flows were visible from the coastal area. By early afternoon, large channelized surface flows broke out between 630 and 180 m elevation. In the days that followed, much of the surface of the flow field above Paliuli was covered by new flows. By 5 December the flows had begun to consolidate. Two flows, on the W and the central part of the flow field, had come together and were close to Paliuli W of the Laeapuki area. One large flow had advanced down the E side of the flow field on Pulama pali, and on 6 December cascaded over Paliuli inland of the former Kamoamoa village site. Fingers from this flow headed for the ocean but stagnated within 200 m of the coast on 16 December. The E flow continued to break out at the base of Paliuli, and by 19 December the distal end was close to the ocean in the Kamoamoa area. Lava on the W side of the flow field cascaded over Paliuli on 7 December. This W flow appeared to be less voluminous than the E flow, and by 19 December breakouts from this flow had only advanced 500 m from the base of Paliuli. Both the E and W flows had breakouts active along much of their length above and below Paliuli. Lava flows were active on Pulama pali for most of this interval. On 20 December, the E flow entered the ocean in the Kamoamoa area. By 2 January 1995 the new entry had not yet consolidated, and several small streams were entering the ocean across a 300-m-wide area. Breakouts were active on this flow for much of this period, particularly near Paliuli. The W flow remained active and fed multiple active breakouts below Paliuli. By the end of this interval, the terminus of this flow was within 500 m of the ocean. Flows continued to break out above Paliuli and on Pulama pali, but none advanced to the coastal plain.

The collapse pit on the W flank of Pu`u `O`o grew during this interval, eroding more tephra on the uphill (E) side of the pit. If this growth continues, the summit of Pu`u `O`o may soon be engulfed. The pond in Pu`u `O`o was active throughout December, at 80-88 m below the crater rim.

Eruption tremor . . . persisted in banded patterns near background levels, alternating with amplitudes of 2-3x background. The number of microearthquakes was low beneath the summit and rift zones. Banded tremor continued up to about 1 January, when the STC (Steam Crack) seismic station, located near Pu`u `O`o, began to register an over-all low-level tremor with minimal banding. Intermediate-depth long-period events were marginally high in number during 22-25 December. Only a few of these events were large enough to be located. The number of short-period microearthquakes was low beneath the summit and rift zones.

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: T. Mattox, HVO.