Most of the earth's volcanoes are formed beneath the oceans, and their locations have been documented in recent decades by mapping of the ocean floor.
(Most of the earth's volcanoes; are formed; L:beneath the oceans) (their locations; have been documented; T:in recent decades; by mapping of the ocean floor)
Most of the earth's volcanoes their locations
are formed have been documented
L:beneath the oceans
T:in recent decades by mapping of the ocean floor