Mulgor Logo Far Infra Gravity Waves: GeoNet Sites


Far infra gravity (FIG) waves are long waves with periods between 2 and 60 minutes.
They are generated by large-scale ocean processes where swell waves that have propagated over vast distances combine into groups with the largest in the middle (surfers' 7th wave phenomenon).
Under the largest waves sea level is depressed slightly and between groups it recovers: this is the FIG wave.
When the swell waves break, the FIG wave is released.
They are also generated by rapidly-propagating low pressure systems such as ex-tropical cyclones.

On this webpage we provide a means to view the far infra gravity waves that have occurred at a tsunami gauge over a set of days that you specify.
The data are then downloaded from the GeoNet site and processed to produce the FIG waves.
From time to time there are gaps in the data. There's nothing we can do about this. Blame GeoNet.

We acknowledge the New Zealand GeoNet project and its sponsors Earthquake Commission (EQC), GNS Science, and Land Information New Zealand (LINZ).

Input Data

Choose the date and number of days you want, then hit Update

Finish Date (UTC):

No of Days:


You can use this page to look at tsunami waves also, but beware!

To retrieve details of the far infra gravity waves at a particular station, click on the name in the map below.
It will take about 10 s to download, process, and plot.