Southern Leyte has common geologic features with Leyte Province on four broad lithogic classifications, namely: a scist body, an igneous complex with serpentinized faceis of probable Cretaceous to Oligocene age; the sedimentary sequence equivalent to that of Samar Island during Early Miocene to Pleistocene epochs; and Quaternary volcanic.
The province is located within the Philippine Rift Zone. The major fault line traverses the municipalities of Sogod, Libagon, St. Bernard, and San Juan to Panaon Island.
Volcanoes occupy present topographic heights and form rugged ridges with irregular slopes in the eastern half of the province. Quatemary volcanic centers are located in the municipalities of Anahawan and San Ricardo.
Overlying the volcanic rocks in the western side of the island is coralline limestone with marly faceis. It exhibits its topographic prominence in the form of north–northwest trending ridges. Solution channels and extensive caves are common features in the western half of the province. The clastic rocks and limestone are found overlying the clastic rocks with late Miocene to early Pliocene epochs.