Pinatubo is part of a chain of volcanoes which lie along the western edge of the island of Luzon.
They are subduction volcanoes which are formed as the Eurasian Plate slides underneath the Philippine Plate along the Manila Trench to the west.
The word 'pinatubo' means 'to have made grow' in the Tagalog and Sambal languages.
This suggests a knowledge of its previous eruption in about AD 1500.