ShakeNZ Examples

ShakeNZ Examples

The images below show actual earthquakes in New Zealand as they would have appeared in ShakeNZ.

Magnitude 5.5 earthquake, 30 km deep near Wellington

Moderate, shallow earthquake - felt regionally, with minor contents damage possible near the epicentre:

Moderate, shallow earthquake - felt regionally, with minor contents damage possible near the epicentre

Magnitude 5.9 earthquake, 100 km deep near Murchison

Moderate, deep earthquake - felt over a wider area than above but not as strongly. No damage expected:

Magnitude 5.9, 100 km deep near Murchison Moderate, deep earthquake - felt over a wider area than above but not as strongly. No damage expected:

Magnitude 4.5 earthquake, 15 km deep near Auckland

Light, shallow earthquake - felt only locally, but in this case by many people. No damage expected:

Magnitude 4.5, 15 km deep near Auckland Light, shallow earthquake - felt only locally, but in this case by many people. No damage expected

Non-Earthquake Cases

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 appear as elevated readings on a cluster of several stations. The map below shows:

  • Empty squares: a data outage in the lower North Island.
  • Orange square: an isolated strong ground motion reading near Christchurch. Significant earthquakes will colour many squares at once, whereas if a disturbance is very local, such as people walking nearby, it will cause only that one detector to show an elevated colour reading.
  • Blue square: low-level elevated seismic noise on White Island.
Non-Earthquake Cases Examples

More about 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.

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.

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.