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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 NZ Volcanic Alert Level system ranges from 0 to 5 and defines the current status at an active volcano. The alert level system is divided into 3 parts: Level 0 a quiet non active volcano, no volcanic unrest; Levels 1 and 2 define the level of ‘volcanic unrest’ and Levels 3, 4 and 5 define the size and impact of eruptions (minor, moderate and major). The alert levels are used by various responding agencies to guide any appropriate response (e.g. MCDEM, CDEM, DOC). For example: Level 2 indicates moderate to heightened volcanic unrest, while Level 3 is a minor volcanic eruption.

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.

Ruapehu lahar monitoring

Techniques used in monitoring Mt Ruapehu include:

  • Visual observations: 2 web cameras facing the north-west and north-east flanks of Ruapehu.
  • Seismic monitoring: 10 seismographs and 6 microphones to detect volcanic explosions.
  • Chemical analysis: Water and gas chemistry and airborne gas measurements.
  • Ground deformation: 8 continuous GPS (CGPS) stations.

Current volcano status