Locality and surroundings
Ulawun is an active volcano located on the border of East New Britain and West New Britain of provinces of Papua New Guinea. The provincial boundary splits its cone in half; the north and south portions as part of the West and East New Britain provinces respectively. The volcano is dubbed the “father” with its two sons; Likuranga (North son) to the northeast and Bamus (South son) to the southwest. It is the highest volcano in PNG, standing 2334m above sea level. Bialla, the nearest major town lies approximately 47km to the SW and Kimbe, the provincial capital town is about 200km further west.
Around Ulawun, oil palm plantations extend up its gentle slopes. Major establishments include; the Catholic Mission station at Ulamona on the western foot and Oil palm estates infrastructures all around its proximity. Oil palm plantations and other developed regions occupy about 10-20% of the 30km radius danger zone. Most of the forest vegetation remain around the southern to south-eastern quadrant of the base of the volcano. The upper extremity of natural forest varies between 1300-1500m above sea level. The top most region from there is about 9 to 10 square km of bare cap of ash, scoria, volcanic blocks and bombs and lava fragments.
Morphology and geology
Ulawun is a typical strato-volcano defined by a conical shape with steep slopes. Deep major avalanche valleys rundown the north-western, western and the south-eastern flanks. A remnant of what seemed to be an older cone mantles over its southern flanks forming an escarpment trending east-west. Smaller gullies and drainages scar the almost-perfect cone of the volcano all around. Notable secondary cones and craters lie in a north-westerly trend with the newly formed NW vent in 2019. Others lie in the east, west and northeast. The steepness of Ulawun’s cone reflects its typical explosive eruptive activity throughout its recorded eruptive history.
Ulawun is part of the Bismarck volcanic arc group of volcanoes. Its location in relation to its formation well reflects the studied relationships between South-Bismarck-Solomon Sea plate tectonics and volcanism in the region. Eruptions at Ulawun is mainly explosive but there are effusive eruptions as well. In 1970, 1973, 1978 and recently in 2019, effusive style eruptions accompanied explosive events. The 1978 and 2019 effusive eruptions are from flank sources; 1978 event is from the lower eastern and 2019 from the upper western flanks. The frequency and style of Ulawun’s eruptions are mostly determined by the magmatic composition with magma chamber pressure-temperature conditions behind every eruption event. Magmatic composition displayed by Mt Ulawun’s eruption products is mostly basalt, although minor but significant variations exist.
The volcano has a long-recorded eruption history dating back as early as the 1700s. Early accounts of eruption sightings were firsts recorded by William Dampier on the 11th of March 1700. Records gradually became complete after 1898 as more observations and records were taken. Details of earlier events are vague but the 1st confirmed major eruption was in 1915. Following years from 1918, 1919, 1927, 1941 and 1957/58 only minor eruptions were recorded. Ulawun then had major eruptions in 1960, 63, 67, 70, 73, 78, 80 and 1985-86. Intermittent minor eruptions were recorded in 1989, 91, 93-94 and 1999. A major eruption occurred in 2000-2001 and after almost 20 years of quiescence, Ulawun erupted again in 2019. There were no casualties throughout the eruption history of Ulawun volcano. However, major impacts in terms of population displacement, infrastructure damages and disruption to vital services are common and ever present. Long term impacts are social and health related issues from ashfall and volcanic gases among others.
Monitoring and volcanic hazards
Rabaul Volcano Observatory uses Seismic, Volcanic Gas and Geodetic Survey techniques to monitor Ulawun Volcano. Seismic monitoring is the major technique used in monitoring Ulawun as similar to all monitored volcanoes in PNG. Permanent seismic stations have been installed near the volcano. Volcanic gas monitoring is also employed in monitoring Ulawun. A permanent gas monitoring station (NOVAC-DOAS) is located where volcanic emissions can be measured effectively. Geodetic survey measurements are done on an even-driven campaign basis using mainly GPS units.
Volcanic hazards at Ulawun are mostly ashfall, pyroclastic flow, Lava flow, mudflow and bombs/blocks. Volcanic hazard zones are shown on available hazards maps reflecting areas where these hazards usually fall. It is best to understand these hazards and where they usually occur to prevent disasters. Ulawun volcanic hazard maps are open to the general public and also for various specific needs of certain stakeholders.
Davies, R.A., 1972. The 1970 Eruption of Ulawun Volcano. Bureau of Mineral Resources, Geology and Geophysics. Department of National Development, Australia. Record 1972/13. View/download
Johnson, R.W., 1981. Notes on the Activity of Ulawun Volcano 1700-1958: Results of a Literature search. In Cooke-Ravian Volume of Volcanological Papers. Geological Survey of Papua New Guinea Memoir 10, 147-151. Google scholar View/download
Johnson, R.W., 1970. Ulawun Volcano, New Britain: Geology, petrology and Eruptive History between 1915 and 1967. Bureau of Mineral Resources, Geology and Geophysics. Department of National Development, Australia. Record 1970/21. Google scholar View/download
McKee, C.O., Almond, R.A., Cooke, R.J.S., Talai, B., 1981.Basaltic pyroclastic avalanches and flank effusion from Ulawun volcano in 1978. In Cooke-Ravian Volume of Volcanological Papers. Geological Survey of Papua New Guinea Memoir 10, 153-165. Google scholar View/download
Werner, C., Schipper, I., Kern, C., Itikarai, I., Bosco, J., Chewings, J., Stewart, C., Carn, S., 2019. Preliminary report on the geochemistry of the 26 June 2019 eruption products from Ulawun Volcano, Papua New Guinea. In Prep.