Here in the Gulf of Alaska, chains of volcanic mountains are lined up across the seafloor. These underwater mountains were created as the tectonic plates moved over volcanic hotspots. Starting from high above the Bering Sea we will fly through this field of seamounts. The first mountains we fly by are the oldest at almost 35 million years and become younger as we go to the southeast. Some of the volcanoes at the southeast ends of these chains are still active. Image courtesy of Exploring Alaska's Seamounts 2002, NOAA/OER.