West Coast tsunami hazards

A 2015 study to identify the risk of tsunami affecting Port Waikato, Raglan Harbour and Aotea Harbour has found that:

• tsunami wave heights from all sources modelled are relatively small
• flooding of low lying areas may occur if the tsunami occurs during a high tide
• tsunami arrival times for the most common sources are between three and six hours, but with the peak tsunami activity occurring several hours after the first arrival
• tsunami arrival times for distant sources from South America are between 15 and 17 hours.

Despite the relatively small tsunami heights, all the scenarios produced potentially dangerous currents particularly at the entrance to each harbour. In each case, these dangerous currents continued for many hours.

The study was funded by Waikato District Council, Waikato Regional Council and WEL Networks.