VOLCANO ALERT SIGNALS
ALERT LEVEL

CRITERIA

INTERPRETATION

No alert Background, quiet No eruption in foreseeable future
1 Low level siesmic fumarol, other unrest Magmatic, tectonic or hydrothermal disturbance; no eruption imminent
2 Moderate level of seismic, other unrest, with + evidence for involvement of magma (A) Probable Magmatic intrusion; could eventually lead to an eruption

(B) If trend shows further decline, volcano may soon go to level 1

3 Relatively high unrest incl. numerous b-type earthquakes, fumaroles, gas emission (A) If trend os one of increasing unrest, eruption is possible within 2 weeks

(B) If trend is one of decreasing unrest, volcano may soon go to level 2

4 Intense unrest incl. harmonic tremor and/or "long period" (=low frequency) earthquakes Eruption possible within 24 hrs.
5 Eruption in progress Eruption in progress