The
Hawaiian–Emperor seamount chain is a mostly undersea mountain range in the Pacific that reaches above sea level in
Hawaii. It is composed of the
Hawaiian ridge, consisting of the islands of the Hawaiian chain northwest to
Kure Atoll, and the Emperor Seamounts: together they form a vast underwater mountain region of islands and intervening
seamounts,
atolls, shallows, banks and reefs along a line trending southeast to northwest beneath the northern
Pacific Ocean. The seamount chain, containing over 80 identified undersea volcanoes, stretches over from the
Aleutian Trench in the far northwest Pacific to the
Loʻihi seamount, the youngest volcano in the chain, which lies about southeast of the
Island of Hawaiʻi.