Report on Bagana (Papua New Guinea) — June 2004
Bulletin of the Global Volcanism Network, vol. 29, no. 6 (June 2004)
Managing Editor: Richard Wunderman.
Bagana (Papua New Guinea) MODVOLC thermal alerts peak in July 2003 and April 2004
Please cite this report as:
Global Volcanism Program, 2004. Report on Bagana (Papua New Guinea). In: Wunderman, R (ed.), Bulletin of the Global Volcanism Network, 29:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200406-255020.
Papua New Guinea
6.137°S, 155.196°E; summit elev. 1855 m
All times are local (unless otherwise noted)
MODVOLC alerts occurred at the same rate as in 2001-2002 (BGVN 28:01), with quasi-continuous alerts from January 2003 to May 2004 (figure 6). These were mostly one- or two-pixel alerts with an average alert ratio of -0.712. On 21 July 2003 activity appeared to have intensified, with an alert ratio of -0.328 and three alert pixels detected. By 13 August 2003 activity was back to 'normal' levels. Then on 18 April 2004, activity picked up again, with a maximum alert ratio for this period of -0.135, along with a maximum number of four alert pixels on 22 April (Aqua satellite) and 6 May 2004 (Terra satellite).
|Figure 6. MODIS thermal alerts from Bagana for 1 January 2001-31 May 2004. Thermal alerts collated by Charlotte Saunders and David Rothery; data courtesy of the Hawaii Institute of Geophysics and Planetology's MODIS thermal alert team.|
Data acquisition and analysis. Reports from Diego Coppola and David A. Rothery provided analyses of MODIS thermal alerts during 2001 and 2002 (using the MODVOLC alert-detection algorithm) extracted from the MODIS Thermal Alerts website (http://modis.hgip.hawaii.edu/) maintained by the University of Hawaii HIGP MODIS Thermal Alerts team (BGVN 28:01). Rothery and Charlotte Saunders provided updates to 31 May 2004. MODVOLC data are now routinely available from the Aqua satellite (equator crossing times 0230 and 1430 local time) in addition to the original Terra satellite (equator crossing times 1030 and 2230 local time).
Geologic Background. Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. This massive symmetrical cone was largely constructed by an accumulation of viscous andesitic lava flows. The entire edifice could have been constructed in about 300 years at its present rate of lava production. Eruptive activity is frequent and characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50 m thick with prominent levees that descend the flanks on all sides.
Information Contacts: David A. Rothery and Charlotte Saunders, Department of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom.