Sumatra Tsunami at New Zealand Ports and Harbours 

Introduction

The Sumatra Tsunami of Boxing Day 2004 propagated around the entire globe, as indicated in this figure showing the maximum wave height from computer modelling done by the NOAA/PMEL team. The propagation path of the tsunami from its origin to New Zealand is extremely tortuous: the continent of Australia is directly in its path, but more importantly the seafloor is highly variable, with many trenches and shoals between Sumatra and New Zealand. Tsunami waves feel every fluctuation of the seafloor and respond to them. Therefore, it is no surprise that the response of the ocean around New Zealand was highly variable. And as the waves propagated into harbours, they modified further in response to the shape of the harbour and its bed.

The purpose of this webpage is to present a summary of the tsunami waves that were measured in the various ports and harbours around New Zealand. An important point that arises from viewing these plots is that each port or harbour responded differently. Therefore, each port needs to assess the risk of their port to tsunami attack. There is no overall formula that can be applied to all ports.

Summary of the Waves

In the table below, we present a summary of the tsunami waves at each port. Detecting the time of arrival (TOA) of the first waves was not easy for some sites because there were long waves present already, and the first tsunami waves were very small. This was true for all ports. The same happened in the Peru Tsunami of 2001. The first waves were very small and they built up over a day or more. This is interesting because it differs from the image many researchers have of a tsunami being a train of solitary waves led by the largest. Indeed, the tsunami waves recorded at NZ ports look very similar to meteorologically-generated long waves, only with periods several times longer.

Sumatra Tsunami at New Zealand Ports
Harbour First Waves Highest Wave
TOA h Height mm Period min TOA h
Bluff 18.4 220 37 38.9
Gisborne 18.1 389 47 83.6
Jackson Bay 18.3 908 26 44.8
Kaipara 19.8 221 78 64.2
Lyttelton 25.0 477 54 40.9
Manukau 21.9 306 54 52.7
Napier 21.2 661 34 48.3
Nelson 23.1 644 45 51.6
Otago 18.4 265 29 53.2
Taranaki 20.2 604 33 37.0
Tauranga 25.2 103 70 61.9
Timaru 18.1 1046 43 48.6
Waitemata 25.3 76 55 43.1
Wellington 24.3 235 31 51.9
Whangarei 24.5 255 37 52.5

TOA=Time of Arrival in hours after the earthquake.

Details at Individual Harbours

To retrieve details of the tsunami waves in a particular harbour, click on the name in the map below:

Timaru Lyttelton Otago Bluff Jackson Bay Wellington Nelson Napier Gisborne Tauranga Waitemata Whangarei Kaipara Manakau Taranaki

How were these calculated?
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Enquiries: Derek Goring
Mulgor Consulting Ltd
24 Brockworth Place
Riccarton, Christchurch
New Zealand
Phone: 64 3 343 5400
Fax: 64 3 343 5403
Email: d.goring[at]mulgor.co.nz