fault- an unattractive or unsatisfactory feature, especially in a piece of work or in a person's character.

primary waves-Primary waves are alternatingly compressional and extensional, and cause the rocks they pass through to change in volume.

seismic waves-an elastic wave in the earth produced by an earthquake or other means.

earthquake-a sudden and violent shaking of the ground, sometimes causing great destruction, as a result of movements within the earth's crust or volcanic action.

compression-the action of compressing or being compressed.

epicenter-the point on the earth's surface vertically above the focus of an earthquake.

fault zone-Large faults within the Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as subduction zones or transform faults.

secondary wave-Secondary waves cause the rocks they pass through to change in shape.

magnitude-the great size or extent of something.

Strike-slip fault: a type of fault where rocks slide horizontally past each other in opposite directions, with little up or down motion. The San Andreas fault in California and the North Anatolian fault in Turkey are examples of strike-slip faults.

Surface waves: seismic waves that move along Earth's surface. They can have an up-and-down motion or a horizontal motion. Surface waves travel slower than P or S waves and usually cause the most damage.

Tension: a type of stress that stretches rock and makes it thinner.

Tsunami: a giant, fast-moving wave that is caused by an undersea earthquake. Also known as a seismic sea wave.

Richter scale: a measurement of the magnitude of an earthquake based on the readings of a seismograph. The Richter scale is a logarithmic scale ranging from 0 to 9, with each number representing a 10-fold increase in ground motion, and a 30-fold increase in energy released.

Seismograph: an instrument that records seismic waves.

Stress: a force that causes rock to change shape.

Reverse fault: a type of fault where compression pushes rock together. Also known as a thrust fault.

Normal fault: a type of fault where forces of tension are pulling rock apart.

Two  plates sliding past each other forms a transform plate boundary. Natural or  human-made structures that cross a transform boundary are offset—split into  pieces and carried in opposite directions. Rocks that line the boundary are  pulverized as the plates grind along, creating a linear fault valley or  undersea canyon. As the plates alternately jam and jump against each other,  earthquakes rattle through a wide boundary zone. In contrast to convergent and  divergent boundaries, no magma is formed. Thus, crust is cracked and broken at  transform margins, but is not created or destroyed.