Report on Rabaul (Papua New Guinea) — May 2006
Bulletin of the Global Volcanism Network, vol. 31, no. 5 (May 2006)
Managing Editor: Richard Wunderman.
Rabaul (Papua New Guinea) Gas emissions and earthquakes during March-April 2006
Please cite this report as:
Global Volcanism Program, 2006. Report on Rabaul (Papua New Guinea) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 31:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200605-252140
Papua New Guinea
4.2459°S, 152.1937°E; summit elev. 688 m
All times are local (unless otherwise noted)
Despite minor inflationary movements that began in mid-February 2006, Tavurvur remained relatively quiet from the end of March to mid-April 2006. Variable amounts of white vapor were released from the summit area and from an active fumarole on the upper W flank during this period. Vapor emissions became denser during and after rainfall. There were no noises heard or visible glow detected at night. Seismic activity remained at a low level. A high-frequency earthquake that originated NE of the caldera was recorded on 22 March. No other distinct high-frequency events were recorded, but 53 low-frequency earthquakes were recorded during 1-14 April.
Geological Summary. The low-lying Rabaul caldera on the tip of the Gazelle Peninsula at the NE end of New Britain forms a broad sheltered harbor utilized by what was the island's largest city prior to a major eruption in 1994. The outer flanks of the asymmetrical shield volcano are formed by thick pyroclastic-flow deposits. The 8 x 14 km caldera is widely breached on the east, where its floor is flooded by Blanche Bay and was formed about 1,400 years ago. An earlier caldera-forming eruption about 7,100 years ago is thought to have originated from Tavui caldera, offshore to the north. Three small stratovolcanoes lie outside the N and NE caldera rims. Post-caldera eruptions built basaltic-to-dacitic pyroclastic cones on the caldera floor near the NE and W caldera walls. Several of these, including Vulcan cone, which was formed during a large eruption in 1878, have produced major explosive activity during historical time. A powerful explosive eruption in 1994 occurred simultaneously from Vulcan and Tavurvur volcanoes and forced the temporary abandonment of Rabaul city.
Information Contacts: Ima Itikarai and Herman Patia, Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea.