Della-Pasqua, F.N.; Massey, C.I.; McSaveney, M.J.; Townsend, D.B. 2016 Preliminary assessment of some flank-failure scenarios for Mount Taranaki and recommendations for future assessment of the risk from such hazards. Lower Hutt, N.Z.: GNS Science. GNS Science report 2015/54 48 p.
Abstract: The ring plains of Mount Taranaki record a number of flank-collapse events in the recent geological past. Volcanic flank collapse is a low probability, high-impact event and the aim of this report is to present results of a preliminary study to inform risk assessments for these types of events. The study comprised: i) a review of flank-collapse trigger mechanism, ii) simplified slope stability analyses of a Mount Taranaki profile and, iii) recommendations for monitoring, investigation and assessment of the potential for flank collapse. Within the range of input parameters tested, the results from 25 modelled scenarios suggest that earthquake loading, groundwater rise, and pressurisation by cryptodome intrusions, each have potential to trigger flank collapse at Mount Taranaki, and should be further investigated. To quantify the impact of these triggers, as well as the likely volume of debris that could be produced from such an event, the actual volcanological and geotechnical data informing credible failure mechanisms need to be ascertained. The validity of the results presented here remains highly conceptual and without further geotechnical data, the uncertainty within the models is large. If flank deformation was identified, then more robust numerical analyses could be carried out to better assess possible failure scenarios and the likely runout distances and volume of debris material during failure. Such information is critical for risk assessment. (auth)
