Mercalli Scale Crust Mantle Plate Tectonics P-wave S-wave focus epicenter seismograph Richter Scale Tsunami fault

A scale of earthquake intensity based on observation of the effect produced by ground motion. The full name is The modified mercalli scale of earthquake intensity. Back

Comparatively thin, outer most layer of the earth. The crust of the earth is an active region. Back

Thick (2,900 km), semi-solid layer of the Earth between the crust and outer core. The top 100 km of so is rigid it is known as the Lithosphere. It, combined with the crust, formed rigid forms of plates and it makes up the earth’s surface. BackBack Back

A theory describing the movement of and interaction between large segments of the earth’s lithosphere. Back

The actual location along a fault, usually at some depth, were earthquake originally originates. The focus is usually some tens of kilometers below the surface. The location on a fault where there is the greatest amount of movement is called the focus. Back

The epicenter is the point on the surface that is directly above the focus. The location on the surface of the earth directly above the point (focus) is where an earthquake occurs. Back

An instrument that is used to measure the ground motion resulting from an earthquake is known as a “Seismograph”. It measures the ground motion graphically Back

A scale of earthquake magnitude based on seismograph recordings, that is a measure of the amount of energy released from the earthquake. Back

Japanese word for “giant waves”. It travels at speeds up to 800 km\h in a open ocean unlike m\normal waves that remain small in height when the water is deep. Back

A crack in the rocks body along where there has been such movement. Earthquakes occur when rock masses in the outer layer of the earth move suddenly along ruptures in the earths crust called faults. Back

In earthquake wave in such particles in the medium vibrate perpendicular to the wave direction, similar to the shaking of a rope. Since the S- wave travels more slowly than a P-wave, it is the second wave to arrive. BackBack

Also known as the compression wave. A type of earthquake wave in which the particles in the medium vibrate parallel to the wave direction. It is the first wave to arrive at a seismographic station. Back