A ridge of submarine mountains marks the place where two massive tectonic plates are moving apart
Although the Pacific Ocean has an average depth of about 4,000 metres, there are shallower regions. Lying approximately 2,000 kilometres off the North American coast is the East Pacific Rise. This oceanic ridge rises about 2 kilometres from the ocean floor, and stretches from the Gulf of California to the southernmost tip of South America. Submarine ridges owe their formation to the movement of the continental plates. As these plates slowly move away from each other, they leave gaps in the earth’s crust. This allows molten rock from beneath the earth’s crust to move up into the gap, forming a new part of the ocean floor. As the molten rock seeping through these gaps is under some pressure, it spews upward, forming a ridge. This upward movement formed the East Pacific Rise, which separates the Pacific Ocean into its East and West Basins. This large ridge reaches the edge of the North American Continental Plate at the Pacific-North American plate boundary.