Volcanic Alert Levels

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.

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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