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dc.contributor.authorGreen, Rebecca
dc.date.accessioned2015-06-09T23:53:46Z
dc.date.available2015-06-09T23:53:46Z
dc.date.issued2015
dc.identifier.urihttp://hdl.handle.net/10179/6684
dc.description.abstractThe estimation of hazard arising from volcanic eruptions is a research topic of great interest to New Zealand, given the number and location of active and dormant volcanoes. Probabilistic temporal models are required to handle the stochastic nature of observed records. Such models are usually assembled using point process techniques or renewal theory and most are purely temporal in the sense that they only consider the distribution of event or inter-event times as predictors of further volcanic activity. I demonstrate using a high-resolution eruption record from Mt Taranaki (New Zealand) how geochemical data can be incorporated, using a proportional hazards type approach, to improve the performance of current renewal-type models. Probabilistic forecasting relies on the accuracy and completeness of historical eruption records. This poses the question of how to establish a detailed record of past volcanic events. Multiple sites are needed to build a composite tephra record, but correctly merging them by recognizing events in common and site-speci c gaps remains complex. I present an automated procedure for matching tephra sequences, using stochastic local optimization techniques. Implausible matches are eliminated through careful reasoning, while heuristically searching over the remaining alternatives. Possible matches are veri ed using known tephra compositions and stratigraphic constraints. The method is applied to match tephra records from ve long sediment cores in Auckland, New Zealand. The correlated record compiled is statistically more likely than previously published arrangements from this area. In addition to the matching of tephras found in the Auckland region, the algorithm is applied to stratigraphic records obtained from Mt Taranaki. With more detailed geochemical information available, matches are constrained further by considering principle component analysis of titanomagnetite compositional data. Finally, after combining the amalgamated record of Mt Taranaki events with point thickness measurements, the eruptive volume of Mt Taranaki events is estimated. Utilizing isopach maps and individual point observations a model is formulated, in a Bayesian framework, for the thicknesses of tephra deposits as a function of the distance and angular direction of each location. The model estimates, in addition to eruptive volume, the wind and site-speci c e ects on the thickness deposits. The ndings lead on to methods of incorporating eruptive volumes in hazard estimation.en_US
dc.language.isoenen_US
dc.publisherMassey Universityen_US
dc.rightsThe Authoren_US
dc.subjectVolcanic eruptionsen_US
dc.subjectHazard estimationen_US
dc.subjectMt Taranakien_US
dc.subjectMount Taranakien_US
dc.subjectVolcanic activity statisticsen_US
dc.subjectHazard estimation modelsen_US
dc.titleStatistical methods for assembling and incorporating volcanic records in hazard estimation : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Statistics at Massey University, Palmerston North, New Zealanden_US
dc.typeThesisen_US
thesis.degree.disciplineStatisticsen_US
thesis.degree.grantorMassey Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophy (Ph.D.)en_US


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