Using maps and graphics, Smithsonian geologist Dr. Liz Cottrell provides an overview of the major earthquake and tsunami that struck Japan on March 11, 2011—one of the largest ever recorded globally. She explains the Pacific “Ring of Fire,” the movement of tectonic plates and subduction, the concept of earthquake magnitude, and the formation of tsunamis. Dr. Cottrell is also director of the Global Volcanism Program at the Smithsonian’s National Museum of Natural History.
UPDATE: When this video was produced, the Japan earthquake was measured at a 8.9 magnitude. Since then, USGS has upgraded the earthquake to a 9.0.