to move in a back and fourth direction.

*S-wave- a seismic wave that causes particles of rock to move in a side to side direction.

*Fault- a break in earths crust along which blocks of crust slide relative to one another

*Epicenter-the point on earths surface vertically above the focus of an earthquake.

*Focus-the center of interest or activity

*Transform Boundary- Transform boundaries are places where plates slide sideways past each other

*After shock-a smaller earthquake following the main shock of a large earthquake.

*Richter scale- a numerical scale for expressing the magnitude of an earthquake on the basis of seismograph oscillations. The more destructive earthquakes typically have magnitudes between about 5.5 and 8.9; the scale is logarithmic and a difference of one represents an approximate thirtyfold difference in magnitude.

Earthquakes are among the most deadly natural hazards. There are around 100 earthquakes each year of a size that could cause serious damage.

Earthquakes strike without warning and many of the Earth’s earthquake zones coincide with areas of high population density. When large earthquakes occur in such areas the results can be catastrophic, with terrible loss of human lives and untold economic cost.

Seismology is the study of earthquakes and seismic waves. The seismograph records theseismic waves generated by earthquakes, allowing the seismologist to determine where , and how deep, a particular earthquake is.

Also, the seismic waves from earthquakes can be used to image the deep interior of the Earth, providing vital clues to the internal structure of our planet.

*In Japan mythology, a giant catfish called Namazu is responsible for earthquakes.

*An average earthquake lasts around a minute.

*The “focus” or “hypocenter” is the earthquake’s initial point of rupture. Its “epicenter” is the point at ground level above the hypocenter.

*More earthquakes happen in the Northern Hemisphere than in the Southern Hemisphere.

*An earthquake under the ocean can cause a tsunami, which travels outward in all directions up to 600 miles (970 km) per hour, the speed of a jet. When the tsunami reaches the shoreline, it suddenly rolls up to heights of over 100 feet (30 meters) causing massive destruction.

The intensity of shaking that a building or structure will experience during an earthquake is highly variable, but generally depends on three main factors:

The magnitude of the earthquake—in general, the larger the quake, the stronger the shaking and the larger the area affected.

The distance from the earthquake—the closer to the source of the earthquake, the greater the shaking.

The type of ground material beneath the structure—soils may amplify or deamplify the shaking relative to hard bedrock.

The variables above will also affect the kind of damage done. Below is a list of various kinds of damage that may occur.