What is the difference between faulting folding and shearing

Folding is generally a plastic response to compressive stress, although some brittle behaviour can happen during folding. An upward fold is an anticline.

A downward fold is a syncline. The axis of a fold can be vertical, inclined, or even horizontal. If we know that the folded beds have not been overturned, then we can use the more specific terms: anticline and syncline.

Fractures joints typically form during extension, but can also form during compression. The site also includes book information and links to additional resources. Tour of the Hayward Fault more info This photographic tour of the Hayward Fault presents images of some of the most easily recognized surface features, from the City of Fremont in central California toward the southern end of the fault, across the Oakland-Berkeley region, northward to Point Pinole on the margin of San Pablo Bay.

The history of earthquakes in the region and potential damage is discussed. Southern California ShakeOut more info These compelling earthquake simulations show ground movement and wave propagation as an earthquake rupture propagates along the San Andreas Fault.

These simulations are from the Great Southern California ShakeOut earthquake drill conducted in The animations capture the shaking at length scales larger than about ft m and provide detailed animations of the shaking for this scenario earthquake. Several different views are available. The files are QuickTime and are available in three different resolutions.

Igneous and metamorphic rocks tend to be stronger and thus resist deformation to a greater extent than sedimentary rocks. The strike of a surface is the direction of a line formed by the intersection of a rock layer with a horizonal surface. The strike is described in terms of direction such as N 10 o W. The dip is measured at right angles to the strike and is a measure of the angle at which the surface tilts relative to a horizontal surface.

The dip is indicated in terms of angle and direction e. Layered rocks folded into arches are called anticlines whereas troughs are referred to as synclines. Figures The two limbs come together to form an imaginary line called the fold axis. The direction in which the fold axis points indicates the strike of the fold. Rock bands appearing on one side of the fold axis are duplicated on the other side.

For basins and domes, strata exposed at the surface form concentric circles around a central point Figure Rock exposures become progressively younger towards the axis of synclines. Rock layers dip away from the fold axis in anticlines, but dip toward the fold axis in synclines.

Reverse and thrust faults form in sections of the crust that are undergoing compression. A convergent plate boundary is a zone of major reverse and thrust faults. In fact, subduction zones are sometimes referred to as mega-thrust faults. Reverse and thrust faults also occur in other settings where the crust is being compressed, such as the Transverse Mountain Ranges, just north of Los Angeles.

Strike-slip faults are steep or vertical faults along which the rocks on either side have moved horizontally in opposite directions. A transform plate boundary is a zone of large strike-slip faults. The San Andreas fault is an example of a major strike-slip fault at a transform boundary. Strike-slip faults also occur in other settings. Skip to main content. Crustal Deformation. Search for:. Physical Behavior of Rocks: Stress and Geologic Structures Before exploring geologic structures, we need to look at how rocks respond to the forces that create the structures.

There are three basic types of stress that deform rocks: compression pushing together tension pulling apart shear twisting or rotating In response to stress, rocks will undergo some form of bending or breaking, or both. Folds Ductile rocks behave plastically and become folded in response to stress. Anticlines and Synclines The most basic types of folds are anticlines and synclines. Plunging Anticlines and Synclines A plunging anticline or a plunging syncline is one that has its axis tilted from the horizontal so that the fold is plunging into the earth along its length.

Basins and Domes A basin is a bowl-like depression in the strata layers of rock. Faults A fault is a planar surface within the earth, along which rocks have broken and slid. The rocks above a fault are called the hanging wall. The rocks beneath a fault are called the footwall. Normal and Detachment Faults In a normal fault, the hanging wall has moved down relative to the footwall.