Earthquakes happen when the boundaries of the Earth's tectonic plates bump and slide past one another; sometimes, they get stuck on jagged edges and cause earthquakes once they are released. These earthquakes are always followed by aftershocks starting from the same epicenter.Continue Reading
The Earth's four main layers are the inner core, outer core, mantle and crust. The crust and the mantle make up a "skin" on the outside of the planet, but is not made of a single piece. The pieces of the mantle and crust are called tectonic plates with the outer edges of each of them called plate boundaries. The section where two plates meet and move is called a fault. As each of the plate boundaries get caught on each other, the rest of the tectonic plate keeps moving and energy begins to store at the point of friction.
When the energy overcomes the friction caused, all of the energy is released and radiates from the epicenter. These waves of energy are called seismic waves and ripple like water on a pond when a stone is dropped in. They often reach the surface of the planet where everything starts to shake. This is why cities or towns that are located near faults are more likely to feel earthquakes than those in the center of a tectonic plate.Learn more about Earthquakes
Most earthquakes happen along the boundaries of the tectonic plates that make up the Earth's crust, though earthquakes can happen anywhere on the planet. Earthquakes are also common along faults, which are deep fissures under great pressure within a plate or along multiple plates.Full Answer >
As of 2015, there are no instruments available that can actually predict an earthquake, but instruments used to detect earthquakes include creepmeters, strainmeters, tiltmeters and pore pressure monitors. These tools are used by the United States Geological Survey in fault lines and volcanoes in the United States. Each tool has a unique and equally important role in helping seismologists determine when earthquakes occur.Full Answer >
Some of the largest earthquakes in the history of the United States include the 1964 Great Alaska earthquake and the earthquake that hit the Cascadia subduction zone in 1700. The 1964 earthquake was 9.2 magnitude, and the 1700 earthquake was 9 magnitude. These are the only earthquakes in the United States to register over 9 magnitude.Full Answer >
Some of the largest earthquakes ever recorded include the Chilean earthquake of 1960, the Prince William Sound earthquake of 1964 and the earthquake in Sumatra, Indonesia, in 2004. Other large earthquakes occurred in Sendai, Japan, in 2011 and Kamchatka, Russia, in 1952. While even larger earthquakes may have occurred in the past, the technology did not yet exist for accurate measurements and records.Full Answer >