Final answer:
Volcanic arcs are curving island chains across the sea floor that are mainly volcanic in origin. One example is the Hawaiian island chain, which was formed by a hot spot.
Step-by-step explanation:
Volcanic Island Chains
The curving island chains across the sea floor that are mainly volcanic in origin are called volcanic arcs. These arcs form where an oceanic plate collides with either a continental or oceanic plate and subducts beneath it. One example of a volcanic arc is the Hawaiian island chain, which was formed by a hot spot located far from a plate boundary.