Volcano hazards, White Island

Scott, B.J.; Nairn, I.A.; Wood, C.P. 1995 Volcano hazards, White Island . Lower Hutt: Institute of Geological & Nuclear Sciences Institute of Geological & Nuclear Sciences science report 95/36 ii, 25 p.

Abstract: Volcanic hazard in the Main Crater of White Island varies considerably with the state of the volcano, being greater during periods of enhanced activity, but not zero during quiescent periods. Hazards to people on the island are therefore considered under 2 scenarios: (a) Hazards arising from an unpredictable ('' blue sky'') isolated explosions, occurring during or at the end of an otherwise quiescent period; and (b) Hazards existing during a period of enhanced activity. White Island is an active volcano and any activities on the Main Crater floor, ranging from casual visits, through chartered tourist trips to large scale scientific investigations, involve a degree of risk. A volcano surveillance programme has operated since 1967 and has helped to develop an understanding of the volcanic processes at White Island. However, one of the outcomes is the realisation that there are no reliable short-term precursors to the potentially damaging large discrete explosive eruptions. The ground deformation monitoring has proven efficient at detecting intrusions of magma to relatively shallow levels, from which periods of enhanced eruptive activity are fed. Mitigation measures can lessen the degree of risk to certain hazards, but real-time monitoring will not provide any reliable short term prediction capability. Any activities undertaken onshore should be designed to lessen the risk. (auth)