Images

A diagram showing three stress types: tensional stress, compressional stress, and shear stress. 

Cross-section of the Earth with lithosphere, mantle, and the core divided into the metallic liquid core and the solid inner core.

En echelon shears crossing street, Hayward Hayward, California. The street shows en echelon shears crossing Foothill Boulevard in San Leandro, just to the north of Hayward. Here the shear zone is quite narrow.

Diagram showing the epicenter and hypocenter. 

The epicenter is the point on the earth's surface vertically above the hypocenter (or focus), point in the crust where a seismic rupture begins.

Fault plane diagram. (Image courtesy of Kian H. Chong, Univ. of California, Davis)

Diagram of frequency. The frequency is the number of times something happens in a certain period of time, such as the ground shaking up and down or back and forth during an earthquake.

Geodesy is the science of determining the size and shape of the earth and the precise location of points on its surface.

Map showing intensity for the New Madrid earthquake. (Image courtesy of the Central U.S. Earthquake Consortium)

A magnetic polarity reversal is a change of the earth's magnetic field to the opposite polarity. This has occurred at irregular intervals during geologic time. Polarity reversals can be preserved in sequences of magnetized rocks and compared with standard polarity-change time scales to estimate geologic ages of the rocks.

Person sitting and overlooking valley of snow-topped mountains with clouds in between mountains 

A stress vs time graph showing fault strength and an offset across fault vs time graph 

Seiche in Lake Geneva (Switzerland)

A seiche is the sloshing of a closed body of water from earthquake shaking. Swimming pools often have seiches during earthquakes.

The shadow zone is the area of the earth from angular distances of 104 to 140 degrees from a given earthquake that does not receive any direct P waves. The shadow zone results from S waves being stopped entirely by the liquid core and P waves being bent (refracted) by the liquid core.

Soil profile in hills of Manisa Province, Turkey, showing a distinct horizon of accumulated red-purple metallic (manganese and/or iron?) oxides.

The standard deviation is how much a set of data is different from the curve it should make when plotted on a graph. Or, the square root of the average of the squares of deviations about the mean of a set of data. Standard deviation is a statistical measure of spread or variability.

When the force trying to make the block (m) slip becomes greater than the frictional force causing it to stick, the block will slip.

The dots on the left make a regular pattern, but the dots on the right make a random, or stochastic, pattern.

Strain is the small changes in length and volume associated with deformation of the earth by tectonic stresses or by the passage of seismic waves.

Teleseismic is pertaining to earthquakes at distances greater than 1,000 km from the measurement site.

A transform fault is a special variety of strike-slip fault that accommodates relative horizontal slip between other tectonic elements, such as oceanic crustal plates. Often extend from oceanic ridges.

A velocity structure is a generalized regional model of the earth's crust that represents crustal structure using layers having different assumed seismic velocities.