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ShakeNZ Information
More about the ShakeNZ interactive application.
ShakeNZ
What is ShakeNZ?
ShakeNZ shows ground shaking in New Zealand. It does not rely on knowing where the earthquake has occurred. Ordinarily it takes the GeoNet Duty Officer between 15 and 30 minutes to determine an earthquake's location and magnitude. Whilst you are waiting for that information to come through to the website, ShakeNZ will give you an interim picture of the likely impact of the earthquake.
What do the maps show?
The maps show the maximum shaking experienced by our seismic instruments during the last 60 minutes. Data is updated every minute, and is graded using the Modified Mercalli (MM) intensity scale. Significant earthquakes will appear on a cluster of stations with MM intensities of 4 or greater.
The symbols are sized according to the expected impact:
- MM 3 or less: unlikely to have been felt.
- MM 4 to 5: generally felt, but no damage likely.
- MM 6 to 7: contents damage possible.
- MM 8 or above: structural damage possible.
What can I do with the controls?
- Use the refresh button to ensure you are viewing up-to-the-minute maps.
- Use the 'alt' button to view an alternative, HTML-only version of the latest data.
- Use the slider to see how the map looked at any time over the previous 60 minutes.
What else should I know?
Some of our stations can take several minutes to send in their data after an earthquake, so the maps you see can only depict the known shaking at a particular time.
Occasionally our instruments are subject to disturbance by people or animals and their activities; these may show up as an isolated high shaking reading. Real earthquakes will appear as elevated readings on a cluster of several stations.
