Geologic Background:
Pago is a young post-caldera cone that was
constructed within the 5.5 x 7.5 km Witori caldera.
Extensive pyroclastic-flow deposits are associated with
formation of the caldera about 3300 years ago. The gently
sloping outer flanks of Witori volcano consist primarily
of dacitic pyroclastic-flow and airfall deposits produced
during a series of five major explosive eruptions from
about 5,600 to 1,200 years ago. The Buru caldera, which
may have formed around the same time, cuts the SW flank
of Witori volcano. The post-caldera cone of Witori, Mount
Pago, may have formed less than 350 years ago. Pago has
grown to a height above that of the Witori caldera rim. A
series of nine dacitic lava flows from Pago covers much
of the caldera floor. The youngest of these was erupted
during the 20th century and banks against the eastern
caldera wall.
Historic Activity:
- Most recently producing lava in the early 1920s and
ash eruptions in 1933.
Recent Activity:
Data Sources:
- Global Volcanism Network (V. 15, No. 10).
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