Numerical modelling of tsunami effects at two sites on the Coromandel Peninsula, New Zealand: Whitianga and Tairua-Pauanui

TR 2013/24
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Report: TR 2013/24

Author: eCoast Limited Marine Consulting and Research

Abstract

This report details a tsunami inundation modelling study for two sites on the Coromandel Peninsula, New Zealand. We use the latest scientific literature on tsunami sources and high-resolution bathymetry grids to produce inundation predictions for Whitianga and Tairua – Pauanui. The model settings and parameters are established through sensitivity analyses and comparison of model results to historical data. This includes instrumental data recoded on the Whitianga tide gauge during the 2010 Chile and 2011 Japan tsunamis as well as eyewitness accounts regarding the wave activity and inundation extents from the 1960 Chile tsunami in Whitianga. The model result are also compared and contrasted with the model results previously presented by Prasetya et al. (2008) for Whitianga.

Numerical modelling of tsunami effects at two sites on the Coromandel Peninsula, New Zealand: Whitianga and Tairua-Pauanui [PDF, 3.8 MB]

Contents
1 Executive summary i
2 Introduction 11
1.1 Review of recent literature 12
1.2 Modelling approach 12
1.3 Numerical modelling grids 13
2 Earthquake source models 16
2.1 1960 Chile earthquake and tsunami 162.2 Kermadec trench scenarios 19
2.3 Additional South American tsunami sources: Peru and Northern Chile 21
3 Model calibration and sensitivity analysis 23
3.1 Model grid configurations 23
3.2 Calibration with Japan 2011 tsunami data 25
3.3 The February 2010 chile tsunami 27
3.4 1960 Chile tsunami 28
3.4.1 Effect of grid configuration 28
3.4.2 Effect of slip distribution 30
3.4.3 Effect of friction coefficient 31
3.4.4 Qualitative comparison to historical accounts 35
3.5 Model results for 1960 on the revised whitianga bathymetry 40
3.6 Kermadec trench source: effect of grid configuration 42
3.7 Kermadec trench source: sensitivity to segment location: 43
3.8 Summary of the model calibration and sensitivity analysis 45
3.9 Arrival times at Whitianga and Tairua-Pauanui from tk scenarios 46
4 Model results: Tairua Pauanui 48
4.1 Far field sources 51
4.2 Kermadec trench sources 54
5 Model results: Whitianga 60
5.1 Far field sources 60
5.2 Kermadec trench scenarios 64
6 Site visit 69
6.1 Tairua 70
6.2 Pauanui 73
6.3 Whitianga 77
7 Extreme scenario inundation maps 80
8 References 86