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Hydrodynamic modelling of tsunami inundation in Whitianga

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Report: TR 2011/01

Author: G Prasetya, Prof. TR Healy, Dr. W de Lange (Coastal Marine Group, Department of Earth and Ocean Sciences - University of Waikato)

About this report

In 2006, Waikato Regional Council provided research funding for the Coastal Marine Group, Department of Earth and Ocean Sciences, University of Waikato to undertake research on the impacts of tsunami inundation on Whitianga town and harbour.

This report addresses the following issues:

  • Potential tsunami sources likely to significantly affect Whitianga township and lowland coastal areas.
  • The hydrodynamic (forces exerted by tsunami waves) processes and response of the bays, inlets, and adjacent coastal land areas to tsunami wave action.
  • The interaction of tsunami run up and overland flows on coastal land areas with existing infrastructure and possible future development areas.
  • Mitigation measures for the community, including, but not limited to:
    • evacuation routes
    • shelter sites
    • public infrastructure (such as power and rest homes)
    • protection of the marina, harbour, Whitianga Waterways and other coastal developments; and
    • educational outreach material for the community and visitors to the area.

Read or download the report

Hydrodynamic modelling of tsunami inundation in Whitianga (5mb)

Contents

Executive summary
Introduction
Background
Historical and potential tsunami sources
Distant tsunami sources
Regional / local tsunami sources
Hydrodynamic modelling of tsunami
 Numerical model
 Model grids
Wide area model grid
Regional and local nested grid models
Modelling results
Potential sources - wide area model
Initial conditions
 Mt Healy eruption
 Kermadec Trench earthquake
 The 1960 Chilean tsunami
Regional model 50m grid
 Mt Healy eruption
 Kermadec Trench earthquake
 The 1960 Chilean tsunami
 Summary of wide area and regional model results
 Local grid model
 Kermadec Trench suduction normal fault event (Mw 9.0)
 1960 Chilean tsunami
Tsunami hazards and risks - flow depths, flow speeds and hazard zones
Tsunami flow depths
Tsunami flow speeds
Tsunami hazard zones
High risk zone
Moderate risk zone
Low risk zone
High risk estuarine zone
Discussion
Summary of results
Evacuation routes and shelter sites
Buffalo Beach Scenic Reserve
Airfield area (corner of Racecourse Road and Whitianga Bypass)
Marina parking area
Vertical evacuation
Overland flow velocities and the building code
Coastal defence structures
Safety planning for ships and boats
Location of critical facilities
Information and education programmes
Bibliography
Appendix 1: Kermadec trench normal fault event scenario inundation sequence and extent
Appendix 2: 1960 Chilean-type scenario inundation seqence and extent
Appendix 3: Animations of tsunami simulation results