The Volcanic Alert Level System
FREQUENTLY ACTIVE CONE
VOLCANOES
VOLCANIC
ALERT
LEVEL
White Island, Tongariro -Ngauruhoe, Ruapehu,
Kermadecs
Volcano Status
Usual dormant or
quiescent state.
Northland, Auckland, Mayor Island, Rotorua, Okataina,
Taupo, Egmont/Taranaki
Indicative
Phenomena
Indicative Phenomena
Typical background surface
activity; seismicity,
deformation and heat flow
at low levels.
Departure from typical
background surface activity.
0
Minor eruptive
activity.
Onset of eruptive activity,
accompanied by changes to
monitored indicators.
2
Significant local
eruption in
progress.
Increased vigour of ongoing
activity and monitored
indicators.
3
Hazardous local
eruption in
progress.
Significant change to
ongoing activity and
monitoring indicators.
Effects beyond volcano.
Destruction with major
damage beyond volcano.
Significant risk over wider
areas.
4
Signs of volcano
unrest.
Large hazardous
eruption in
progress.
REAWAKENING VOLCANOES
1
5
Typical background surface
activity; seismicity,
deformation and heat flow
at low levels.
Apparent seismic, geodetic,
thermal or other unrest
indicators
Increase in number or
intensity of unrest
indicators (seismicity,
deformation, heat flow etc.).
Minor eruptions. High
increasing trends of unrest
indicators, significant
effects on volcano and
possibly beyond.
Eruption of new magma.
Sustained high levels of
unrest indicators, significant
effects beyond volcano.
Destruction with major
damage beyond active
volcano. Significant risk
over wider areas.
Volcano Status
Usual dormant or
quiescent state.
Initial signs of possible
volcano unrest. No
eruption threat.
Confirmation of volcano
unrest. Eruption threat.
Minor eruptions
commenced. Real
possibility of hazardous
eruptions.
Hazardous local eruption
in progress. Large scale
eruption now possible.
Large hazardous volcanic
eruption in progress.
ICAO Aviation Volcano Level - Colour Code
ICAO Colour code
Status of activity of volcano
GREEN
Volcano is in normal, non-eruptive state. or, after a change from a higher alert level: Volcanic activity
considered to have ceased, and volcano reverted to its normal, non-eruptive state.
YELLOW
Volcano is experiencing signs of elevated unrest above known background levels. or, after a change
from higher alert level: Volcanic activity has decreased significantly but continues to be closely
monitored for possible renewed increase.
ORANGE
Volcano is exhibiting heightened unrest with increased likelihood of eruption.
or, Volcanic eruption is underway with no or minor ash emission [specify ash-plume height if possible].
RED
Eruption is forecasted to be imminent with significant emission of ash into the atmosphere likely. or,
Eruption is underway with significant emission of ash into the atmosphere [specify ash-plume height if
possible].
Volcanic Alert Levels
Volcanic Alert Level
Radius from Vent (nm)
RUAPEHU Volcanic Hazard Zone (NZV 314)
0
1
2
3
4
5
Upper Limit
see note 1
3
3
8
16
27
>50
12,200ft AMSL
12,200ft AMSL
FL 150
FL 330
FL 480
Unlimited
NGAURUHOE Volcanic Hazard Zone (NZV 313)
0
1
2
3
4
5
3
3
8
16
27
>50
10,500ft AMSL
10,500ft AMSL
FL 150
FL 330
FL 480
Unlimited
TONGARIRO Volcanic Hazard Zone (NZV 312)
0
1
2
3
4
5
3
3
8
16
27
>50
9,500ft AMSL
9,500ft AMSL
FL 150
FL 330
FL 480
Unlimited
WHITE ISLAND Volcanic Hazard Zone (NZV 211)
0
1
2
3
4
5
3
3
8
16
27
>50
4,500ft AMSL
4,500ft AMSL
FL 150
FL 330
FL 480
Unlimited
RAOUL ISLAND Volcanic Hazard Zone (NZV 010)
0
1
2
3
4
5
3
3
8
16
27
>50
5,000ft AMSL
5,000ft AMSL
FL 150
FL 330
FL 480
Unlimited
ANY OTHER NZ VOLCANO Volcanic Hazard Zone (NZVxxx)
0
1
2
3
4
5
1
3
3
8
16
27
>50
3000 ft above top of vent
3000 ft above top of vent
FL 150
FL 330
FL 480
Unlimited
At the start of an eruptive episode at Ruapehu, the presence of the Crater Lake will suppress the formation of
significant ash clouds, as the eruption develops and the lake is removed, ash clouds will become more common.