In New Zealand, Volcano Alert Bulletins (VABs) are the official source of warnings and alerts including current Volcanic Alert Level (VAL), [1] intended to inform stakeholder agencies, authorities, and the public about emergencies so they can take action.
The Ministry of Civil Defence & Emergency Management, through The National Emergency Management Agency is responsible for providing such alerts to warn about natural hazards. [2] A Scientific Alert Level is applied to the Volcano Status based on Indicative Phenomena. GNS Science operates the national geological hazards monitoring network (GeoNet). [3]
The Volcanic Alert Level system has six levels ranging from 5 (major volcanic eruption) to 0 (no volcanic activity): [4]
| Volcanic Alert Level | Volcanic Activity | Most likely hazards | Example |
|---|---|---|---|
| 5 | Major volcanic eruption | Eruption hazards on and beyond volcano | – |
| 4 | Moderate volcanic eruption | Eruption hazards on and near volcano | 2019 Whakaari / White Island eruption |
| 3 | Minor volcanic eruption | Eruption hazards near vent | – |
| 2 | Moderate to heightened volcanic unrest | Volcanic unrest hazards, potential for eruption hazards | Whakaari / White Island in 2019 before eruption [5] [6] |
| 1 | Minor volcanic unrest | Volcanic unrest hazards | – |
| 0 | No volcanic unrest | Volcanic environment hazards | – |
To help prevent harm when living or working on or near a volcano, countries have adopted classifications to describe the various levels and stages of volcanic activity, the two main volcano warning systems being colour codes and/or numeric alert levels. [7]
The three common popular classifications of volcanoes can be subjective, and some volcanoes thought to have been extinct have erupted again.
Volcanic Alert Level Summary
Whakaari/White Island Alert Level