Changes to the Volcanic Alert Level system

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From 1 July 2014, New Zealand has changed its definitions of the Volcanic Alert Level (read about the changes here). These are now the current definitions; the old definitions are retained below these ones. In several weeks they will be removed to a separate page.

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.

 

 

New Zealand Volcanic Alert System

 

Volcanic
Alert
Level

Volcanic Activity

Most Likely Hazards

Eruption

5

Major volcanic eruption

Eruption hazards on and beyond volcano*

4

Moderate volcanic eruption

Eruption hazards on and near volcano*

3

Minor volcanic eruption

Eruption hazards near vent*

Unrest

2

Moderate to heightened volcanic unrest

Volcanic unrest hazards, potential for eruption hazards

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.

  File Modified
PDF File VAL_system-v3.0_purple.pdf The New Zealand Volcanic Alert System (official graphic, suitable for printing). May 19, 2014 by Kevin Fenaughty

 

The old Volcanic Alert Level system

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From 1 July 2014, the following definitions have become historical, but should still be referenced when reading Volcanic Alert Bulletins set before this date:

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 (in the Okataina Volcanic Centre) or Taupo.

Frequently Active Cone Volcanoes

Alert Level

Indicative Phenomena

Volcano Status

0Typical background surface activity; seismicity, deformation and heat flow at low levels.Usual dormant or quiescent state.
1Departure from typical background surface activity.Signs of volcano unrest.
2Onset of eruptive activity, accompanied by changes to monitored indicators.Minor eruptive activity.
3Increased vigour of ongoing activity and monitored indicators. Significant effects on volcano, possible effects beyond.Significant local eruption in progress.
4Significant change to ongoing activity and monitored indicators. Effects beyond volcano.Hazardous local eruption in progress.
5Hazardous large volcanic eruption in progress.Large hazardous eruption in progress.

Reawakening Volcanoes

Alert Level

Indicative Phenomena

Volcano Status

0Typical background surface activity; seismicity, deformation and heat flow at low levels.Usual dormant or quiescent state.
1Apparent seismic, geodetic, thermal or other unrest indicators.Initial signs of possible volcano unrest. No eruption threat.
2Increase in number or intensity of unrest indicators (seismicity, deformation, heat flow, etc.).Confirmation of volcano unrest. Eruption threat.
3Minor steam eruptions. High-increasing trends of unrest indicators, significant effects on volcano, possibly beyond.Minor eruptions commenced. Real possibility of hazardous eruptions.
4Eruption of new magma. Sustained high levels of unrest indicators, significant effects beyond volcano.Hazardous local eruption in progress. Large scale eruption now possible.
5Destruction with major damage beyond active volcano. Significant risk over wider areas.Large hazardous volcanic eruption in progress.
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