The regions tropical, humid climate sustains vegetation that carpets much of the island. A jagged line of small, round volcanic craters extends east-west across the island (top of image). South of this uneven line, two deep, parallel valleys extend toward the south. The semicircular contours of the valleys suggest that they might be the remains of an ancient caldera or collapsed magma chamber that was modified by the later eruption of additional lava.
With the exception of a few brown crater rims, and a coastal settlement along the images left edge, the landscape appears in varying shades of green. Dense rainforests cover the islands rugged interior, and thick vegetation also thrives along the coastal plains. Savaii has remained volcanically active into historical times, with two eruptions occurring in the early 20th century.
The eruptions sent big lava flows to the islands northern coast, destroying several villages.