Ash fall prediction in New Zealand


  • T. Poirot University of Canterbury, Christchurch, New Zealand
  • J. Cole University of Canterbury, Christchurch, New Zealand
  • D.G. Elms University of Canterbury, Christchurch, New Zealand



The North Island of New Zealand contains seven active volcanoes or volcanic centres, and ash fall from these centres could present health hazards and other problems. Part of the required contingency planning for ash fall is the assessment of the frequency and depth of ash fall at any point. The issue is particularly important for urban areas likely to be affected. This paper develops a theory for ash fall frequency assessment based on estimated eruption frequencies and magnitudes and on meteorological data. The theory is used to obtain the ash fall frequency/depth relationship for the Napier /Hastings area in the Hawkes Bay region. The results show that the annual frequency of significant ash fall in the towns is high enough to justify some degree of emergency preparedness, with a fall of 1 mm having an annual exceedance probability of about 0.05, or in other words a return period of approximately 20 years.


Armienti, P., Macedonio, G. & Pareschi, M.T. (1988). "A numerical model for the distribution of tephra transport and deposition: applications to May 18, 1980 Mt. St. Helens eruption". Journal of Geophysical Research, 93, 6463-6476. DOI:

Barry, R.G. & Chorley, R.J. (1992). "Atmosphere, Weather and Climate". Routledge, London, 392p.

Carey, S. & Sigurdsson, H. (1982). "Influence of particle aggregation on deposition of distal tephra from the May 18, 1980 eruption of Mount St. Helens volcano". Journal of Geophysical Research, 87, 7061-7072. DOI:

Carey, S. & Sigurdsson, H. (1989). The intensity of plinian eruptions. Bulletin of Volcanology, 51, 28-40. DOI:

Carey, S. & Sparks, R.SJ. (1986). "Quantitative models of the fallout and dispersal of tephra from volcanic eruption columns". Bulletin of Volcanology, 48, 109-125. DOI:

Cornell, C.A. (1968). "Engineering seismic risk analysis". Bulletin of the Seismological Society of America, 58, 1583-1606.

Dalziell, E. (1998). "Risk assessment methods in road network evaluation: a study of the impact of natural hazards on the Desert Road, New Zealand". PhD Thesis, University of Canterbury, Christchurch, New Zealand.

Eden, D.N., Froggatt, P.C., Trustrum, N.A. & Page, M.J. (1993). '"A multiple-sourced Holocene tephra sequence from Lake Tutira, Hawke's Bay, New Zealand". New Zealand Journal of Geology and Geophysics, 36, 233-242. DOI:

Eden, D.N. & Froggatt, P.C. (1996). "A 6,500 year old history of tephra deposition recorded in the sediments of Lake Tutira, Eastern North Island, New Zealand". Quaternary International, 34-36, 55-64.

Elms, D.G. (1992). "Consistent crudeness in system construction". ln B.H.V. Topping (Ed), Optimisation and Artificial Intelligence in Civil Engineering, Kluwer Academic Publishers, v.1, 61-70. DOI:

Houghton, 8.F., Wilson, C.J.N., McWilliarns, M.O., Lanphere, M.A., Weaver, S.D., Briggs, R.M. & Pringle, M.S. (1995). "Chronology and dynamics of a large silicic magmatic system: Central Taupo Volcanic Zone, New Zealand". Geology, 23, 13-16. DOI:<0013:CADOAL>2.3.CO;2

Howorth, R., Froggatt, P.C. & Robertson, S.M. (1980). "Late Quaternary volcanic ash startigraphy of the Poukawa area, Central Hawke's Bay, New Zealand". New Zealand Journal of Geology and Geophysics, 23, 487-49 I. DOI:

Hurst, A.W. (1994). "ASHFALL - A computer program for estimating volcanic ash fallout: report and users guide". Science Report 94/23. Institute of Geological and Nuclear Sciences.

Hurst, A. W. & Turner, R. (1999). "Performance of the program ASHFALL for forecasting ashfall during the 1995 and 1996 eruptions of Ruapehu volcano". New Zealand Journal of Geology & Geophysics, 42, 615-622. DOI:

Johnston, D.M. & Nairn, I.A. (1993). "Volcanic impacts report: the impact of two eruption scenarios from the Okataina Volcanic Centre on the population and infrastructure of the Bay of Plenty Region, New Zealand". Resource Planning Publication 93/6. Bay of Plenty Regional Council.

Johnston, D.M. (l997). "Physical and social impacts of past and future volcanic eruptions in New Zealand". Ph.D. Thesis, Massey University, Palmerston North, New Zealand.

Latter, J.H. (1985). "Frequency of eruptions at New Zealand volcanoes". Bulletin of the New Zealand National Society for Earthquake Engineering, 18, 55-110.

Lowe, DJ. (1988). "Late Quaternary volcanism in New Zealand: towards an integrated record using distal airfall tephras in lakes and bogs". Journal of Quaternary Science, 3(2), 111-120. DOI:

Lowe, DJ., Newham, R.M. & Ward, C.M. (1999). "Stratigraphy and chronology of a 15 ka sequence of multi-sourced silicic tephras in a montane peat bog, Eastern North Island, New Zealand". New Zealand Journal of Geology and Geophysics, 42, 565-579. DOI:

Macedonio, G., Pareschi, M.T. & Sanatacrocc, R. (1988). "A numerical simulation of the plinian fall phase of 79A.D. eruption of Vesuvius". Journal of Geophysical Research, 93, 14817-14827. DOI:

Newhall, C.G. & Self, S. (1982). "The Volcanic Explosivity Index (VEI): An estimate of explosive magnitude for historical volcanism". Journal of Geophysical Research, 87, 1231-1238. DOI:

Page, M.J. & Trustrum, N.A. (1997). "A late Holocene lake sediment record of the erosion response to land use changes in a steepland catchment, New Zealand". Geomorphology, 41:3, 369-392.

Rhoades, D.A., Dowrick, D.J. & Wilson, C.J.N. (2002). "Volcanic hazard in New Zealand: Scaling and attenuation relations for tephra fall deposits from Taupo Volcano". Natural Hazards, 26, 147-174. DOI:

Scott, BJ., Johnston, D.M. & Manville, V. (1998). "Volcanic impacts in the Hawke's Bay region". Client Report 71754D.10. Institute of Geological and Nuclear Sciences.

Stirling, M., Yetton, M., Pettinga, J., Ben-yman, K. & Downes, G. (1999). "Probabilistic seismic hazard assessment and earthquake scenarios for the Canterbury Region, and Historic Earthquakes in Christchurch". Client Report 1999/53. Institute of Geological and Nuclear Sciences.

Sturman, A.P. & Tapper, N.J. (1996). ''The Weather and Climate of Australia and New Zealand". Oxford University Press, Melbourne, 476p.

Wilson, C.J.N., Houghton, B.F., McWilliams, M.O., Lanphere, M.A., Weaver, S.D. & Briggs, R.M. (1995). "Volcanic and structural evolution of Taupo Volcanic Zone, New Zealand: a review". Journal of Volcanology and Geothermal Research, 68, 1-28. DOI:




How to Cite

Poirot, T., Cole, J., & Elms, D. (2004). Ash fall prediction in New Zealand. Bulletin of the New Zealand Society for Earthquake Engineering, 37(4), 181–194.