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.
|Volcanic Alert Level||Volcanic Activity||Most Likely Hazards|
|Eruption||5||Major volcanic eruption||Eruption hazards on and beyond volcano*|
|Eruption||4||Moderate volcanic eruption||Eruption hazards on and near volcano*|
|Eruption||3||Minor volcanic eruption||Eruption hazards near vent*|
|Unrest||2||Moderate to heightened volcanic unrest||Volcanic unrest hazards, potential for eruption hazards|
|Unrest||1||Minor volcanic unrest||Volcanic unrest hazards|
|0||No volcanic unrest||Volcanic environment hazards|
An eruption may occur at any level, and levels may not move in sequence as activity can change rapidly.
Eruption hazards depend on the volcano and eruption style, and may include explosions, ballistics (flying rocks), pyroclastic density currents (fast moving hot ash clouds), lava flows, lava domes, landslides, ash, volcanic gases, lightning, lahars (mudflows), tsunami, and/or earthquakes.
Volcanic unrest hazards occur on and near the volcano, and may include steam eruptions, volcanic gases, earthquakes, landslides, uplift, subsidence, changes to hot springs, and/or lahars (mudflows).
Volcanic environment hazards may include hydrothermal activity, earthquakes, landslides, volcanic gases, and/or lahars (mudflows).
*Ash, lava flow, and lahar (mudflow) hazards may impact areas distant from the volcano.
This system applies to all of New Zealand's volcanoes. The Volcanic Alert Level is set by GNS Science, based on the level of volcanic activity. For more information, see geonet.org.nz/volcano for alert levels and current volcanic activity, gns.cri.nz/volcano for volcanic hazards, and getthru.govt.nz for what to do before, during and after volcanic activity. Version 3.0, 2014.
VALsystem-v3.0purple.pdf - the New Zealand Volcanic Alert System (official graphic, suitable for printing).