Active vs. Extinct

Active = Erupting, recently erupted or likely to erupt.

Dormant = Volcano that has not erupted in 100s to 1000s of years (but could still do so).

Extinct = No longer capable of erupting.

Predicting Eruptions

Volcanoes frequently show predictable signs that they will erupt several days to weeks prior to an eruption. Scientists monitor volcanoes - particularly those in high-risk areas - for these signs so they can warn the public with enough time for them to evacuate the area.

• Earthquake activity: Magma flow increases seismicity.
• Heat flow: Magma causes volcanoes to “heat-up.”
• Changes in shape: Magma causes expansion.
• Emission increases: Changes in gas mix and volume.

These signs indicate that an eruption is imminent. These signs, however, cannot predict the exact timing or the style. Scientist can warn the public that an eruption is likely and evacuation orders can be given, thus saving lives.

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