Both hotspots and mid-ocean ridges are volcanic, so Iceland is doubly so.

ECONOMIST: Volcanoes and air travel: Small eruption in Iceland | The

Given all the discoveries that we have made from an up-close investigation of these ocean ridges, we can't help but wonder what we might find at the far end of the same plate tectonic cycle where seafloor is drawn back into the Earth's interior at deep-ocean trenches.

CNN: Probing the ocean's undiscovered depths

At around 6:30, the rising sun slowly reveals the rolling ridges all around us that seem to move like ocean waves toward the flat Utah deserts to the west.

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