Volcano alert levels: Philippines
The volcano authority in the Philippines is the Philippine Institute of Volcanology and Seismology (Phivolcs). The alert level system used by Phivolcs runs from Alert Level 0 (lowest) to Alert Level 5 (highest), as follows:
Alert Level 0: No Alert.
Quiet. No eruption in the foreseeable future.
Alert Level 1: Abnormal.
Low level unrest. No eruption imminent.
Alert Level 2: Increasing Unrest.
Moderate unrest. Unrest probably of magmatic origin, could eventually lead to eruption.
Alert Level 3: Increasing Tendency Towards Eruption.
Relatively high unrest. Magma is close to the crater.
Alert Level 4: Hazardous Eruption Imminent.
Intense unrest. Hazardous eruption is possible within days.
Alert Level 5: Hazardous Eruption.
Hazardous eruption ongoing.