Coconut Islands 3

Savaii Island, Samoa

The Earth’s crust that lies beneath the Pacific Ocean is broken into numerous pieces, called tectonic plates, which move constantly, colliding, drifting apart, sliding atop one another, driven by convection currents rising from deep within the planet’s mantle, creating a sea floor that is riddled with cracks and gaping holes. In places, the seismic fissures extend from Earth’s molten core to the crust’s surface, providing passageways for fiery streams of magma to leak into the frigid ocean water, where they cool and form undersea mountains. In most spots, the seamounts are not big, appearing simply as topographic blips on the sonar maps of oceanographers. Where they attain greater heights, though, the seamounts may breach the surface of the water to form islands. The central part of the Pacific Ocean — Polynesia — is filled with volcanic islands that were created in this way, taking form as the Pacific plate drifts over weak places, or “hotspots,” in the sub-oceanic mantle. These isolated land fragments remain attached to the fractured and moving lithosphere, and, like tectonic embryos hatched from a Promethean being, are carried through the warm, equatorial waters. On average, the Polynesian islands travel northward at a rate of about four inches per year, which is an astonishingly fast journey through geological time.

Savaii Island, Samoa