San Andreas Fault in the context of "Salton Sea"

An active fault is a fault that is likely to become the source of another earthquake sometime in the future. Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last 10,000 years.

Active faulting is considered to be a geologic hazard – one related to earthquakes as a cause. Effects of movement on an active fault include strong ground motion, surface faulting, tectonic deformation, landslides and rockfalls, liquefaction, tsunamis, and seiches.

A transform fault or transform boundary, is a fault along a plate boundary where the motion is predominantly horizontal. It ends abruptly where it connects to another plate boundary, either another transform, a spreading ridge, or a subduction zone. A transform fault is a special case of a strike-slip fault that also forms a plate boundary.

Most such faults are found in oceanic crust, where they accommodate the lateral offset between segments of divergent boundaries, forming a zigzag pattern. This results from oblique seafloor spreading where the direction of motion is not perpendicular to the trend of the overall divergent boundary. A smaller number of such faults are found on land, although these are generally better-known, such as the San Andreas Fault and North Anatolian Fault.

In geology, aseismic creep or fault creep is measurable surface displacement along a fault in the absence of notable earthquakes. Aseismic creep may also occur as "after-slip" days to years after an earthquake. Notable examples of aseismic slip include faults in California (e.g. Calaveras Fault, Hayward Fault, and San Andreas Fault).

A fault trace describes the intersection of a geological fault with the Earth's surface, which leaves a visible disturbance on the surface, usually looking like a crack in the surface with jagged rock structures protruding outward. The term also applies to a line plotted on a geological map to represent a fault. These fractures tend to occur when a slip surface expands from a fault core, especially during an earthquake. This tends to occur with fault displacement, in which surfaces on both sides of a fault, known as fault blocks, separate horizontally or vertically.

John Tuzo Wilson (October 24, 1908 – April 15, 1993) was a Canadian geophysicist and geologist who achieved worldwide acclaim for his contributions to the theory of plate tectonics. He added the concept of hot spots, a volcanic region hotter than the surrounding mantle (as in the Hawaii hotspot). He also conceived of the transform fault, a major plate boundary where two plates move past each other horizontally (e.g., the San Andreas Fault).

His name was given to two young Canadian submarine volcanoes called the Tuzo Wilson Seamounts. The Wilson cycle of seabed expansion and contraction (associated with the Supercontinent cycle) bears his name. One of the two large low-shear-velocity provinces was given the name Tuzo after him, the other being named Jason after W. Jason Morgan, who furthered Wilson's work into plume theory.

The San Gorgonio Pass, or Banning Pass, is a 2,600 ft (790 m) elevation gap on the rim of the Great Basin between the San Bernardino Mountains to the north and the San Jacinto Mountains to the south. The pass was formed by the San Andreas Fault, a major transform fault between the Pacific plate and the North American plate that is slipping at a rate of 7.2 ±2.8 mm/year. The tall mountain ranges on either side of the pass result in the pass being a transitional zone from a Mediterranean climate west of the pass, to a Desert climate east of the pass. This also makes the pass area one of the windiest places in the United States, and why it is home to the San Gorgonio Pass wind farm.

It serves as a major transportation corridor between the Greater Los Angeles region and the Coachella Valley, and ultimately into Arizona and the United States interior. Both Interstate 10, and the Union Pacific Railroad, utilize the pass. When the rail line was completed in January 1883, by the Southern Pacific Railroad, it was billed as the second U.S. transcontinental railroad.

The San Bernardino Mountains are a high and rugged mountain range in Southern California in the United States. The mountain range is part of the Transverse Ranges and lies north and northeast of San Bernardino and spanning two California counties, the range tops out at 11,503 feet (3,506 m) at San Gorgonio Mountain – the tallest peak in Southern California. The San Bernardinos form a significant region of wilderness and are popular for hiking and skiing.

The mountains were formed about eleven million years ago by tectonic activity along the San Andreas Fault, and are still actively rising. Many local rivers originate in the range, which receives significantly more precipitation than the surrounding desert. The range's unique and varying environment allows it to maintain some of the greatest biodiversity in the state. For over 10,000 years, the San Bernardinos and their surroundings have been inhabited by indigenous peoples, who used the mountains as a summer hunting ground.