Like many places of human settlement, the site of Rabaul (see Fig. 4) is subject to volcanic hazard. This hazard, a consequence of plate subduction processes involving the Pacific and Australian Plate (see Fig. 8) have been responsible for developing the island of New Britain in Papua New Guinea. The area has a geological history of violent eruptions where Simpson Harbour itself is an explosion crater, or caldera (see Fig. 3) and 500 people died in the 1937 eruption. As a consequence of vulcanism, humans benefit from the provision of a safe harbour as well as the potential for fertile soils to develop for farming. Whilst there are benefits gained from the volcanic activity on Rabaul, activity on the 20th September 1994 (see Fig. 10) resulted in significant social, economic and environmental upheaval. Currently, both Tavurvur and Vulcan are active and producing ash to a depth of 75 metres over the township. Appropriate mitigation by authorities must ensure that potentially dangerous hazards to people are avoided. A decision on whether to abandon or re-establish Rabaul will need to consider balancing the risk to residents with the economic and social upheavals that could result.
The explosive eruption of magma, ash, gas and rocks had a significant environmental and socio-economic impact on the Rabaul area. Due to the prevailing South to Southeast winds, ash up to 75 centimetres in depth as well as poisonous gas affected the Rabaul area when Vulcan and Tavuruur erupted explosively (see Fig. 7 & 10). Whilst farmlands to the south [evidenced in the 3-D aspect sketch by Mr Raward] avoided the ash and gas due to the wind direction, had the eruption occurred between November and April, this highly acidic material may well have destroyed these farmlands. The risk of lahar and subsequent flooding is ever present if rain is added to this ash. Collapse of buildings has already occurred as a result of ash build up. The harbour also suffered sedimentation loads from the ash (see Fig. 5). This has a significant impact on the island’s capacity to trade and move its farm stock. Coupled with this impact is the possibility that further destruction of low-lying areas could occur if tsunami activity is present. There is evidence in Figure 10 that “tidal waves” have entered the town. Although it is not clear as to what is meant by this, it may well be the flooding from sedimentation in the harbour, local rivers, or even tsunami activity from offshore tremors. Loss of viable farmland, landlessness, job loss, looting of local businesses and the cost to rebuild are just some of the socio-economic impacts of such a disaster.
A decision to re-site Rabaul to the western end of New Britain minimises risk to residents but will have a significant impact socially and economically on the community. Residents will face inevitable debt, farmers and the community will have to rebuild their lives in a new place, resulting in significant economic and social stress for the people of Rabaul. International aid cannot be guaranteed so costs could become extreme. Without a protected harbour, the settlement will have limited ability to trade and move produce. Nevertheless, safety of residents can be guaranteed as this area is not volcanic.
Re-establishment of damaged sections of Rabaul will result in less socio economic upheaval than a proposal to re-site. Nevertheless, residents will face a greater risk if they remain in Rabaul, as the volcano is in an active phase. A proposal to re-establish is socially sustainable given that it contains safe guards including interest free loans and…