Earthquakes are the result of plate tectonics, or shifting plates in the crust of Earth, and quakes occur when the frictional stress of gliding plate boundaries builds and causes failure at a fault line. In an earthquake, elastic strain energy is released and waves radiate, shaking the ground. Scientists can predict where major temblors might occur in a general sense, but research does not yet allow forecasts for specific locations or accurate predictions of timing. Major earthquakes, some generating tsunamis, have leveled entire cities and affected whole countries. Relatively minor earthquakes can also be induced, or caused by human activity, including extraction of minerals from Earth and the collapse of large buildings.
An odd phenomenon may explain why the Southeastern United States has experienced recent earthquakes, even though the region sits snugly in the middle of a tectonic plate and not at the edges, where all the ground-shaking action usually happens.
A magnitude-7.0 earthquake struck southern Japan today, less than two days after a 6.2-magnitude temblor rocked the same region, triggering tsunami advisories in the area. Why do so many earthquakes strike this part of the world?