Classifications of Volcano
Why does the Philippines have many volcanoes?
According to PHIVOLCS, the Philippines sits on a unique tectonic setting ideal to volcano formation. The archipelago is surrounded by subducting plates as manifested by the trenches that are related to volcano formation.
1) Active volcanoes:
erupted within historical times (within the last 600 years), accounts of these eruptions were documented by man; erupted within the last 10,000 years based on analyses of datable materials.
2) Potentially active volcanoes:
morphologically young-looking but with no historical records of eruption.
3) Inactive volcanoes:
no record of eruptions; physical form is being changed by agents of weathering and erosion via formation of deep and long gullies.