Review of Tsunami Hazard in New Zealand (2013 Update) Compiled by William Power
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Review of Tsunami Hazard in New Zealand (2013 Update) Compiled by William Power GNS Science Consultancy Report 2013/131 August 2013 DISCLAIMER This report has been prepared by the Institute of Geological and Nuclear Sciences Limited (GNS Science) exclusively for and under contract to the Ministry of Civil Defence and Emergency Management. Unless otherwise agreed in writing by GNS Science, GNS Science accepts no responsibility for any use of, or reliance on any contents of this Report by any person other than the Ministry of Civil Defence and Emergency Management and shall not be liable to any person other than the Ministry of Civil Defence and Emergency Management, on any ground, for any loss, damage or expense arising from such use or reliance. The data presented in this Report are available to GNS Science for other use from 13 September 2013. BIBLIOGRAPHIC REFERENCE Power, W. L. (compiler). 2013. Review of Tsunami Hazard in New Zealand (2013 Update), GNS Science Consultancy Report 2013/131. 222 p. Project Number 410W1378 Confidential 2013 CONTENTS EXECUTIVE SUMMARY ...................................................................................................... IX 1.0 INTRODUCTION ........................................................................................................ 1 1.1 SCOPE OF THIS REPORT ................................................................................... 1 1.2 CONTRIBUTORS ............................................................................................... 1 1.3 STRUCTURE OF THE REPORT ............................................................................ 2 1.4 WHAT IS A TSUNAMI? ........................................................................................ 3 1.5 WHAT DAMAGE DOES A TSUNAMI DO? ................................................................ 5 2.0 TSUNAMI IMPACTS................................................................................................... 7 2.1 INTRODUCTION ................................................................................................ 7 2.2 TSUNAMI RISK ................................................................................................. 7 2.3 TSUNAMI IMPACT TYPES ................................................................................... 8 2.4 ASSESSING THE COSTS OF TSUNAMI IMPACTS ...................................................12 2.4.1 Qualitative damage assessments ................................................................... 13 2.4.2 Semi-quantitative damage assessments ........................................................ 14 2.4.3 Quantitative damage assessments ................................................................. 14 2.4.4 Tsunami damage assessments – ex ante ....................................................... 14 2.4.5 Tsunami damage assessment – ex post ......................................................... 25 2.5 REFERENCES..................................................................................................28 3.0 PALEOTSUNAMI AND HISTORICAL TSUNAMI DATABASES .............................. 35 3.1 HISTORICAL TSUNAMI RECORDS .......................................................................35 3.2 LARGE HISTORICAL TSUNAMI ............................................................................39 3.3 RECENT TSUNAMI EVENTS 2005–2011 .............................................................43 3.4 APPLICATION OF THE NEW ZEALAND HISTORICAL TSUNAMI RECORD ...................47 3.5 PALEOTSUNAMI RECORDS ...............................................................................47 3.5.1 Description of paleotsunami ............................................................................ 47 3.5.2 The New Zealand paleotsunami database ...................................................... 49 3.5.3 Recent paleotsunami research 2005–2011 .................................................... 55 3.5.4 Summary of paleotsunami in New Zealand .................................................... 59 3.6 REFERENCES..................................................................................................60 4.0 TSUNAMI MODELLING ........................................................................................... 63 4.1 NUMERICAL MODELS .......................................................................................63 4.2 TSUNAMI GENERATION ....................................................................................65 4.2.1 Submarine earthquakes .................................................................................. 65 4.2.2 Landslides and volcanoes ............................................................................... 67 4.3 PROPAGATION MODELLING ..............................................................................68 4.3.1 Modelling tsunami propagation numerically .................................................... 69 4.3.2 Insights from propagation modelling ............................................................... 73 4.4 INUNDATION MODELLING ..................................................................................77 4.4.1 Numerical modelling of tsunami inundation .................................................... 77 4.5 EMPIRICAL TSUNAMI MODELLING ......................................................................79 GNS Science Consultancy Report 2013/131 i Confidential 2013 4.5.1 Empirical modelling of tsunami heights ........................................................... 79 4.5.2 Empirical modelling of tsunami inundation ...................................................... 80 4.5.3 Deriving rules for defining tsunami evacuation zones ..................................... 80 4.6 REAL-TIME TSUNAMI MODELLING AND FORECASTS .............................................82 4.7 PROBLEMS AND LIMITATIONS OF TSUNAMI MODELLING .......................................85 4.8 TSUNAMI MODELLING STUDIES RELEVANT TO NEW ZEALAND ..............................85 4.8.1 Tsunami modelling studies in New Zealand .................................................... 85 4.9 REFERENCES..................................................................................................86 5.0 DEFINING TSUNAMI SOURCES ............................................................................. 91 5.1 DISTANT SOURCES ..........................................................................................91 5.1.1 Earthquakes .................................................................................................... 91 5.1.2 Landslides ....................................................................................................... 98 5.1.3 Volcanoes ........................................................................................................ 99 5.1.4 Bolide impact ................................................................................................... 99 5.2 REGIONAL SOURCES .....................................................................................100 5.2.1 Earthquakes .................................................................................................. 100 5.2.2 Volcanoes ...................................................................................................... 104 5.2.3 Landslides ..................................................................................................... 105 5.3 LOCAL SOURCES ...........................................................................................108 5.3.1 Earthquakes .................................................................................................. 108 5.3.2 Landslides ..................................................................................................... 113 5.3.3 Volcanoes ...................................................................................................... 117 5.4 REFERENCES................................................................................................118 6.0 PROBABILISTIC MODELLING .............................................................................. 125 6.1 INTRODUCTION AND MOTIVATION ....................................................................125 6.2 METHODOLOGY OUTLINE ...............................................................................125 6.3 TYPES OF UNCERTAINTY AND VARIABILITY .......................................................127 6.4 SOURCE DEFINITION ......................................................................................127 6.5 TREATMENT OF VARIABLE SLIP AND MODELLING UNCERTAINTY ......................... 128 6.6 ESTIMATION OF TSUNAMI HEIGHTS ................................................................. 130 6.7 CALCULATION ...............................................................................................131 6.8 DEAGGREGATION OF TSUNAMI SOURCES ........................................................131 6.9 RESULTS ......................................................................................................132 6.10 COMMENTS AND DISCUSSION OF RESULTS ......................................................169 6.11 FUTURE WORK ..............................................................................................170 6.12 REFERENCES................................................................................................171 7.0 DISCUSSION AND CONCLUSIONS ...................................................................... 173 7.1 SUMMARY .....................................................................................................173