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.
The earthshaking rumblings felt in Michigan last night weren't an earthquake, but rather vibrations from a booming noise caused by a meteor whizzing overhead, according to the National Earthquake Information Center.
The Pacific Northwest sits atop the Cascadia subduction zone, which is a region where two tectonic plates collide; one plate is being pushed deep into the Earth's mantle, beneath the other slab. The two plates get locked together, and when one gives way,
In preparation for the BIG ONE — the mighty 9.0-magnitude earthquake that's expected to lay waste to the Pacific Northwest — geophysicists have created 50 virtual simulations to see how such a quake could rattle the region.