M8.2 Mexico earthquake: Tsunami beach and marine warning cancelled

Published: Fri Sep 8 2017 5:30 PM
Updated: Sat Sep 9 2017 1:45 PM

A beach and marine tsunami warning is no longer in effect for New Zealand following the 8.2M Mexico earthquake

The Ministry of Civil Defence & Emergency Management has cancelled the beach and marine tsunami warning for the Chatham Islands, Banks Peninsula, Pegasus Bay, Northern Coasts of Hawke's Bay and East Cape areas only.

Based on all available data, the tsunami beach and marine threat for the above areas has now passed.

The largest wave amplitude of 35-40cm was recorded at the Chatham Islands. To provide you an understanding of what this looks like, our scientists produced the following plot, which shows the peaks and troughs in the tidal surge past the Chatham Island's gauge. Observations from tidal gauges around other sites of New Zealand have shown that maximum wave amplitudes of 15-25cm.

Plot of the peaks and troughs in the tsunami surge as it passed the Chatham Island tsunami gauge.

Plot of the peaks and troughs in the tsunami surge as it passed the Chatham Island tsunami gauge.

We don't expect any further significantly larger waves to occur for the above areas. However, there is still the possibility of waves less than 20cm, and coastal areas will likely experience unusual, strong currents and surges lasting for several more hours. This means you still need to careful in coastal areas.

Our tsunami gauges picked up clear tsunami activity at our Chatham Island, Gisborne and East Cape sites. However, the updated chart below shows the effects of the Mexico Tsunami, with varied sea level fluctuations indentiable on a number of the nationwide tsunami gauges over the last ~7 hours. This is consistent with our tsunami scientists' predictions, who rapidly identifed that fluctuations in sea level, and potentially strong coastal currents, would likely continue throughout the day.

De-tided nationwide tsunami gauge chart showing tidal effects from the Mexico Tsunami, as at 13:20 NZST - 9 September 2017.

De-tided nationwide tsunami gauge chart showing tidal effects from the Mexico Tsunami, as at 13:20 NZST - 9 September 2017.

Our scientists will continue to monitor the situation through the day and we will provide further updates if necessary in accordance with the Ministry of Civil Defence & Emergency Management.

Only messages issued by the Ministry of Civil Defence & Emergency Management represent the official warning status for New Zealand.

You can read more about our tsunami threats and history here.

We can’t stop tsunamis from happening BUT we can prepare for them. Want to know how? Here are some great places to go to get more information about New Zealand and preparing for tsunamis: