Up the entire west coast of South and North America and down the far east side of Russia and Asia is the "ring of fire" and most of it is comprised of undersea volcanoes. A major area of tectonic plate movement; which just so happens to be the most likely spot to find volcanoes.

https://education.nationalgeographic.org/resource/plate-tectonics-ring-fire/

Up the entire west coast of South and North America and down the far east side of Russia and Asia is the "ring of fire" and most of it is comprised of undersea volcanoes. A major area of tectonic plate movement; and the most likely spot to find volcanoes.

https://education.nationalgeographic.org/resource/plate-tectonics-ring-fire/