GNS Scientists use several different methods to gather and compile volcanic unrest data. The data is analysed to assign a volcanic alert level and an aviation colour code for each volcano.
Volcanic monitoring and interpretation of data is primarily the responsibility of GNS Science, through the GeoNet project, and is based on the understanding that movement of magma (molten rock) beneath a volcano must occur before an eruption can begin. This will appear as volcanic unrest.
Movement of magma under Mt Taranaki is detected by data received from the GeoNet seismic network. GNS staff will respond to increased volcanic unrest by increasing their seismic, geodetic (ground movement), and geochemical monitoring. The Taranaki Seismic and Volcanic Advisory Group (TS-VAG) will provide advisory services to Taranaki Civil Defence throughout any event.
In New Zealand, we use a system of Volcanic Alert Levels to define the current status of each volcano. The alert levels range from 0 to 5. The alert levels are used to guide any appropriate response.
The New Zealand Volcanic Alert System
Brad Scott and Sally Potter explain New Zealand's Volcanic Alert Levels.
It is important to note that although modelling has determined various historic eruption patterns there is no guarantee that future eruptions will follow those patterns. Appropriate science organisations coordinated by GNS (GeoNet) will model and interpret real-life events as they unfold.