(Above) Modelling by eCoast shows how Whangamata could potentially be inundated by a tsunami.
Efforts in tsunami hazard mitigation by eCoast Marine Consulting and Research are in-line with recommendations found in a recent report produced by the New Zealand Earthquake Commission.
Key findings from the EQC-commissioned report ‘Tsunami risk facing New Zealand’ released earlier this month include the need to complete evacuation planning, improve early warning and communication systems and provide better information for decision–makers during tsunami events.
eCoast director and senior consultant Dr Jose Borrero and his team have studied tsunamis for over 20 years and have been working on these issues both in the Waikato region and nationwide for a number of years.
Dr Borrero explains “Our efforts in the Waikato Region include computer modeling of ‘worst-case’ tsunami events for the purposes of evacuation planning. For these studies, we are assuming that a ‘Japan-sized’ earthquake occurs on the large fault line running to the east of New Zealand.”
“This is not fanciful thinking; this kind of earthquake has happened before and could very well happen here. The waves from such an earthquake would reach the Coromandel coast in less than an hour and produce substantial inundation and potential devastation throughout the region,” he adds.
However, eCoast’s studies are not limited to these extreme, yet relatively rare local events. Dr Borrero and eCoast have recently completed a multi-year research project focusing on the more commonly occurring Pacific-wide tsunamis and how they affect New Zealand’s economically vital ports.
Dr Borrero explains that currents caused by a tsunami from across the Pacific can damage or destroy a port without causing any substantial flooding. “This occurred in California after the 2011 Japan tsunami. The Port of Crescent City was destroyed, yet the waters never rose above the high tide mark,” said Dr Borrero.
“Using detailed computer models, we can identify areas within a port or harbour that are particularly vulnerable to tsunami induced currents. We can also determine when these currents will commence and how long they might last – and in most cases, because of the long travel time across the ocean, this can be done before the tsunami arrives on New Zealand shores. This provides ample time for a warning or evacuation order and minimizes the chances of a false alarm.”
Dr Borrero will be presenting some of his findings at the upcoming Coasts and Ports Conference to be held at the Pullman Hotel in Auckland from 16-18 September 2015.