Report on Witori (Papua New Guinea) — 31 December-6 January 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 31 December-6 January 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on Witori (Papua New Guinea). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 31 December-6 January 2003. Smithsonian Institution and US Geological Survey.
Papua New Guinea
5.576°S, 150.516°E; summit elev. 724 m
All times are local (unless otherwise noted)
As of 2 January lava continued to flow from Pago's northwestern-most vent. In addition, variable amounts of white vapor were released from most vents along the fissure system. Weak incandescence was visible on the night of 28 December. Seismicity continued at low levels as it has since early October 2002 when the seismic network was installed. No significant ground deformation had been recorded in a month, in contrast to the period between the start of the eruption (early August) and early November when complex and significant movement was recorded.
Geologic Background. The 5.5 x 7.5 km Witori caldera on the northern coast of central New Britain contains the young historically active cone of Pago. The Buru caldera cuts the SW flank of Witori volcano. The gently sloping outer flanks of Witori volcano consist primarily of dacitic pyroclastic-flow and airfall deposits produced during a series of five major explosive eruptions from about 5600 to 1200 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. Pago has grown to a height above that of 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.