Evacuation planning needed for any future rhyolite eruption from Tarawera Volcano.
Degree GrantorUniversity of Canterbury
Degree NameMaster of Science
Evacuation planning is commonplace throughout the world, as the need for effective planning before an emergency is essential. In New Zealand, the presence of significant natural hazards in the landscape and the potential risks posed to urban communities justify the need for such planning. One of the foremost natural hazards in the North Island ofNew Zealand is that of volcanic eruptions. A large-magnitude eruption from the Okataina Volcanic Centre (OYC) would considerably affect the surrounding Bay of Plenty region, causing the evacuation of c.l50,000 people. A review of current New Zealand civil defence and emergency management (CDEM) practices reveals that there is still a lot to do in the way of large-scale evacuation planning, especially with regard to the long-term sheltering of thousands of evacuees. A review of historical New Zealand evacuation events also reveals that only 14 significant events (>1000 evacuees) have occurred, providing an initial understanding of some of the problems associated with a large-scale evacuation. However, the lack of experience of large-scale evacuation events means that there is little public awareness of the problem. A review of historical global evacuation events further highlights some of the characteristic problems associated with large-scale evacuation, including traffic-related, sheltering and re-entry problems. Both the historical New Zealand and global events provide lessons applicable to a New Zealand setting. Tarawera volcano is an active volcano situated in the OYC, which has had four largemagnitude (>5km³ ) rhyolitic eruptions in the past c.21,000 years. Most notably is the 1314 ± 12AD Kaharoa eruption, the largest eruption to have occurred within New Zealand during the past 1,000 years. A Kaharoa-type eruption provides a valuable scenario, as it is well studied, complex and of long duration. Subsequently, a Kaharoa-type eruption scenario was used as a template on which to base an evacuation plan, incorporating lessons learnt from both the historical New Zealand and global evacuation events. This resultant evacuation plan can be used by CDEM practitioners in the Bay of Plenty region to initiate the formulation of district, regional and national evacuations plans that incorporate and consider the many problems associated with evacuation. The resultant evacuation from a Kaharoa-type eruption occurring today would involve the evacuation of residents from the Bay of Plenty region, primarily from Rotorua, Kawerau, Te Teko, Te Puke, Murupara, Tauranga and Whakatane. Probable destinations for evacuees would be Auckland and Hamilton, with a 100 km radius, 'unsafe-zone' recommended around Tarawera volcano. Evacuation before the main eruption is expected to have less problems associated with it, whereas evacuation during and post-the main eruption will be extremely problematic, emphasising the need for careful planning before an emergency. Most of the Bay of Plenty region will receive at least 10 em of ash fall, but Kawerau and Murupara are likely to receive ~60 em, resulting in significant damage to community lifelines and the necessary evacuation of all residents. New Zealand CDEM need to define the responsibility of evacuation decision-making, create adequate coordination between key agencies, develop sufficient warning methods and methods of confirmation, monitor the adequacy of sheltering facilities for evacuees, including long-term options, and understand the factors that influence evacuation decision-making in residents, combining these with the use of incentives for evacuating.