The twin islands of Ofu (on the west), and Olosega (on the
east) are formed by two sharply eroded, overlapping shield
volcanoes. Steep slopes and cliffs of up to 600 m in height
give the islands dramatic southern and northern coastlines
that sweep to points facing the narrow strait between the
islands; the interiors of the islands slope to the west
(Ofu) and east (Olosega). The steep slopes of Ofu's southern
coast culminate in the Leolo Ridge where the highest peak of
the island is found — the Tumu Mountain at 494 m. Olosega's
Piumafua Mountain, located at the junction of the northern
and southern ridges (Alei Ridge and Mataala Ridge,
respectively) rises to a height of 639 m. Both islands are
surrounded by a common fringing reef that becomes exposed at
low tide.
The narrow Asaga Strait (hidden beneath the
clouds on the right) that separates the islands is spanned
by a small slab and girder bridge.
