Banahaw volcano is a complex of 3 volcanoes 80 km SE of Manila, Philippines. The Banahaw volcanic complex includes Mt Banahaw (2158 m), San Cristobal (1470 m), and Banhao de Lucban (1870 m) volcanoes.
Mild explosive eruptions might still occur at the Banahaw volcano complex, although none of the reports of historic activity can be verified by deposits or credited sources.
Banahaw has a 2-km-wide, 600-m-deep summit crater open to the SSW and contained a crater lake until 1730, when it drained to form mudflows. Similar events took place in 1743?, 1843 and 1909.
A large collapse of the NE flank of Banahaw produced a debris avalanche deposit with a volume of 5 cubic km. The event lest a 8 km wide and more than 1 km deep horse-shoe shaped depression extending from 1700 m to 650 m altitude.
The oldest deposits from Banahaw volcano are known as the Lucena pyroclastic flow deposits, visible on the shore at Tayabas Bay near Lucerna City and at the eastern base of Banhao de Lucban stratovolcano.
Banhao de Lucban is the youngest stratovolcano of the group. It forms a steep cone on the eastern flank of Banahaw volcano, and overlies the debris avalanche of Banahaw volcano, and therefore is younger than that event.
San Cristobal stratovolcano lies on the western flank of Banahaw volcano. It has a youthful shape indicating a younger age than Banahaw. The absence of soil covering the youngest volcanic layer of San Cristobal ("San Cristobal 3 unit") suggest that it might be younger than 2000 years.
