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Report on Witori (Papua New Guinea) — 28 May-3 June 2003


Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
28 May-3 June 2003
Managing Editor: Gari Mayberry

Please cite this report as:

Global Volcanism Program, 2003. Report on Witori (Papua New Guinea). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 28 May-3 June 2003. Smithsonian Institution and US Geological Survey.

Weekly Report (28 May-3 June 2003)


Papua New Guinea

5.576°S, 150.516°E; summit elev. 724 m

All times are local (unless otherwise noted)

An aerial inspection of Pago's summit area on 22 May revealed that lava effusion from the northwestern-most vent had ceased following the last aerial inspection in February 2003. Also, there were no indications of fresh lava near the vents. This observation was confirmed by the lack of further movement of the northerly and southerly lobes of lava. Furthermore, there was no change in the height of the lava body against the caldera wall. Scientists also saw that a new fumarole area had formed between Mt. Pago and the Pyramid to the east. Significant inflation had been measured since December 2002, but it may be related to roadwork in the area causing benchmarks to move.

Geological Summary. The Witori caldera (5.5 x 7.5 km) on the northern coast of central New Britain contains the active Pago cone. The Buru caldera cuts the SW flank. The gently sloping outer flanks consist primarily of dacitic pyroclastic-flow and airfall deposits produced during a series of five major explosive eruptions from about 5,600 to 1,200 years ago, many of which may have been associated with caldera formation. The post-caldera Pago cone may have formed less than 350 years ago; it has grown to a height above the Witori caldera rim, and a series of ten dacitic lava flows from it covers much of the caldera floor. The youngest of these was erupted during 2002-2003 from vents extending from the summit nearly to the NW caldera wall.

Source: Rabaul Volcano Observatory (RVO)