Volcanic Island Formation from a hot spot.
Heat from this hot spot produces magma by melting the overriding Pacific Plate. The magma then rises through the mantel and Earth's crust onto the seafloor forming an active sea-mountain. Over time, countless eruptions cause the sea-mountain to grow until it finally emerges above sea level to form an island volcano. As the plate movement carries the island beyond the hotspot, the magma source is cut off and the volcano becomes dormant. As one island becomes extinct, another develops over the hotspot. This trail of volcanic islands can be seen across the Pacific Ocean floor.