Monitoring volcanic unrest
Scientists at GNS Science use several different methods to gather and compile the data relating to volcanic unrest for New Zealand’s volcanoes. This information is then analysed to assign a volcanic alert level and an aviation colour code for each volcano.
Alert Levels and Colour Codes explained
The Volcanic Alert Level ranges from 0 to 5 and defines the current status at a volcano. The alert levels range from 0 to 5. There are two tables, one for the frequently active volcanoes like Ruapehu and White Island. The second one deals with the reawakening of dormant volcanoes like Mayor Island, Tarawera or Taupo. The alert levels are used by various agencies to guide any appropriate response (e.g. MCDEM, DOC). For example: Level 2 indicates that a minor eruption has occurred.
Aviation Colour Codes are based on four colours and are intended for quick reference only in the international civil aviation community. The Aviation Colour Code reflects conditions at or near a volcano and are not intended to pertain to hazards posed at a distance or downwind by drifting ash. For example: Code Orange indicates that a volcanic eruption is underway but with little or no ash being produced.
Techniques used in monitoring White Island include:
- Visual Observations: 2 web cameras are sited on White Island; one web camera is located on the North Island coast at Whakatane.
- Seismic Monitoring: 1 seismograph and a microphone to detect volcanic explosions.
- Chemical Analysis: Water and gas chemistry samples and soil gas measurements are taken approximately every 12 weeks. Airborne gas monitoring is undertaken regularly but is weather dependent.
- Ground Deformation: Levelling for deformation every three months.