A new study suggests that two recent earthquakes may indicate a literal seismic shift in our understanding of tectonic plate movements. Massive earthquakes under the Indian Ocean that took place last spring are the largest of their kind ever recorded. The 8.7 magnitude quake, followed by a 8.2 magnitude aftershock, could signal the formation of a new plate boundary under the Earth. While not the largest earthquakes ever recorded, the two quakes are notable for their unusual location. The majority of earthquakes are known as thrust faults: massive sheets of rock sliding over or under another block along a fault...