Report on Witori (Papua New Guinea) — July 2005
Bulletin of the Global Volcanism Network, vol. 30, no. 7 (July 2005)
Managing Editor: Edward Venzke.
Witori (Papua New Guinea) Low-level vapor emissions and seismicity through August 2005
Please cite this report as:
Global Volcanism Program, 2005. Report on Witori (Papua New Guinea). In: Venzke, E. (ed.), Bulletin of the Global Volcanism Network, 30:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200507-252080.
Papua New Guinea
5.576°S, 150.516°E; summit elev. 724 m
All times are local (unless otherwise noted)
Pago has remained quiet during April-August 2005, with no reports of volcanism since the end of the most recent eruption in early 2003 (BGVN 28:03 and 28:09). Reports since that time have described low-level emissions and seismicity (BGVN 28:12, 29:02, 29:04, 29:07).
In April the upper vents and the summit crater released small amounts of white vapor and occasional thin white vapor was reported from the lower vents. Seismic activity was low; the daily number of low-frequency earthquakes ranged from zero to a few. In June weak emissions of thin white vapor continued to be released from the upper vents but no emissions were noted from the lower vents. Seismicity in June remained low, with no more than 8 small, high-frequency earthquakes recorded per day. Similar activity continued through August. Visual observations on 27 and 28 August revealed emissions of very small volumes of thin white vapor being released from the upper vents of the fissure system. No emissions originated from the lower or main summit vents. Seismic activity was low throughout the month, and some small high-frequency earthquakes were recorded. The greatest number of high-frequency events recorded on any given day was 7 on 25 August. No noises were heard and no glow was observed during the reporting period.
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.
Information Contacts: Ima Itikarai and Herman Patia, Rabaul Volcano Observatory (RVO), P. O. Box 386, Rabaul, Papua New Guinea.