Earthquakes

A fault is a crack in the Earth’s crust. These occur when plates slide against each other, causing the rock to be twisted, stretched, or squeezed until it splits.

Fault creep is the gradual movement of two pieces of the Earth’s crust scraping against each other along a fault.

The crust is Earth’s solid outer layer. It consists of continental crust, which forms the land, and oceanic crust, which forms the seabed.

Seismology is the study of earthquakes and other smaller movements of the Earth.

Plates are the separate pieces of crust which fit together like a jigsaw puzzle to cover the Earth.

Plate tectonics is the theory that the plates of the Earth’s crust gradually move around and rub against each other.

A tsunami is a giant wave produced when an earthquake or volcano on the seabed causes the water to vibrate.

An earthquake is a sudden release of energy which makes the ground tremble. They are most common near plate boundaries where the movement of the plates causes stress to build.

The Richter scale measures the power of seismic waves. Earthquakes are rated between 1 and 10. Each step up the scale indicates a 30 fold increase in energy released.

A seismic wave is a vibration that travels through the ground when an earthquake happens.

A seismometer is a device that seismologists use to measure seismic waves.

A seismogram is a chart showing the size of the seismic waves measured during an earthquake.

A seismologist is a scientist who studies earthquakes.

A plate boundary exists where two of the Earth’s plates come together.

The focus is the point where the rock gives way, starting the earthquake.

The epicenter is the point on the surface directly above the focus.

Aftershocks are smaller tremors that occur after an earthquake.