Hikurangi Magnitude 9 Workshop
Our Civil Defence Emergency Management team together with NEMA held a workshop in September for agencies and emergency services. The purpose was to consider the response and recovery considerations of a Hikurangi M9 earthquake scenario offshore from Gisborne city. The outcome was to:
- Initiate the development of the regional Hikurangi M9 plan for Tairāwhiti
- Develop the strategic response and recovery plan for Tairāwhiti
- Inform that national planning for Hikurangi M9 regional support
Setting the scene
Recent research has shown that the East Coast from Gisborne to Northland along with Banks Peninsula and the Chatham Islands have been historically hit by tsunami more often than in other parts of New Zealand. The Gisborne Tarāwhiti region is also more vulnerable to future tsunami.
In 1947, 2 relatively small earthquakes triggered local tsunami with wave heights exceeding 10m that had significant impacts from Wainui north to Tolaga Bay. But these were small events compared with the threat posed by a rupture of the Hikurangi Fault that lies off Gisborne and spans the eastern New Zealand north of Marlborough.
The great Japan or Tohoku Magnitude 9 earthquake in 2011occurred on a similar fault and graphically showed the impact a magnitude 9 event will have. Research in Marlborough has shown that two equivalent events have occurred on the Hikurangi Fault in the last 1000 years.
But the last event was 500 years ago and there is a 1:4 chance of another rupture on the Hikurangi Fault occurring in the next 50 years.
Key speakers were:
|David Burbrige (GNS) - Setting the scene convergent margin EQ Rupture.|
|Jose Borrero (eCoast) - The Gisborne city tsunami model and inundation animation|
|Kate Clark (Paleotsunami) - Tsunami database|
|William Power (GNS) - Intelligent agent evacuation modelling|
|Marion Tan (Massey) Georgia (ECLAB) - Social impact modelling|
|James Williams - Auckland University - tsunami impacts on infrastructure|
|NEMA national response|
|Murry Cave (GDC)|