NEMA said severe weather events, exacerbated by climate change, were the new normal, but new research showed there was a 75 percent chance of an Alpine Fault earthquake in the next 50 years with a four out of five chance it would be magnitude 8 or above.
An event like that could disrupt power supply, trap tens of thousands of visitors and isolate residents in Queenstown Lakes, parts of Central Otago, the West Coast and Fiordland as well as trigger landslides and landslide-created tsunamis.
This is one of a number of briefings to incoming ministers released on Thursday. Read more:
NEMA also noted recent research which indicated there was a 25 percent probability of a major Hikurangi Subduction Zone earthquake event occurring in the next 50 years.
Subduction Zones are known for producing the largest earthquakes.
“Indicative national impacts of a major Hikurangi earthquake and tsunami include tens of thousands of people dead, injured or displaced from their homes, and significant damage to the built environment (in excess of $144 billion).”
The document said the frequency of emergency weather events were increasing, putting growing pressure on the agency’s ability to prepare, recover and respond.
It said overall the emergency management system could be easily overwhelmed with a moderate scale event – let alone something larger or more widespread.
This was exacerbated in specific regions where there may not be the capacity to fully respond to and recover from a moderate or even small-scale event.
NEMA used Cyclone Gabrielle as an example, and said – while it caused significant damage and was devastating to the communities involved – this would only be considered a moderate scale event.