This activity is designed to familiarize the learner with the concepts of strike and dip, to make further studies of faults and fault models easier. It also introduces learners to a few key elements of seismology, which will be seen again later in much greater detail. Knowledge of how to solve basic trigonometric equations is needed for this activity. To describe a fault plane in simple terms, geologists ... Full description.

This is a short lesson about scarp formation. The answer is provided as an animated GIF. This example points out a general rule of fault-related geology: the apparent offset of a feature (in this case, level ground offset vertically) is not always an indication of the actual displacement (horizontal cutting of a pre-existing scarp) along a fault. This is one of the more extreme examples of that rule. ... Full description.

This activity has two parts: the first part will demonstrate the weaknesses of simple fault models (like block diagrams) in depicting the process of fault rupture accurately; and the second part is centered around a fairly simple animation of rupture propagation, seen by an oblique map view, that attempts to show more accurately what we should envision when we think about fault rupture. This activity ... Full description.

When plate tectonics causes part of the Earth's crust to compress, as in a zone of collision, or to extend, as in a zone of rifting, faults must form to help accomplish this task. While the deeper layers of rock, due to extreme heat and pressure, can fairly easily deform to accommodate the stretching of rifting or the compression of collision, the brittle rock of the uppermost crust must break and ... Full description.

Some faults experience appreciable amounts of dip slip and strike slip simultaneously, and the nomenclature of these faults reflects this. This is an exercise regarding the nomenclature of faults that experience appreciable amounts of dip slip and strike slip simultaneously. In this activity, learners view animations of these faults and attempt to correctly interpret the sense of motion. Clicking ... Full description.

The orientation and sense of slip of faults in an area is largely dependent upon the tectonic forces present in that area. In this exercise learners are shown several idealized fault-block models and asked to interpret the sense of movement along certain fault planes within a given tectonic environment. Clicking on the images provides the correct answers. Full description.

This guide includes a route and stops that present features of the San Andreas fault in the vicinity of Los Angeles and Wrightwood, California. Students can see different rock types on either side of the fault, representing the Pacific and North American Plates, and other features such as sag ponds, fault gouge, fault valleys, and tilted layers of sediments. Full description.

This article describes the occurrence of listric normal faults (those which gradually flatten out with depth) in the continental shelf offshore Oregon and Washington, as seen in seismic reflection profiles. There is also a discussion of the faulting mechanics, the timing of uplift on the continental shelf, and the separation of compressional and extensional tectonic regimes on the lower and upper ... Full description.

This report describes a structural model proposed to explain sedimentation patterns in the Trinidad area of the East Venezuelan Basin. Full description.

This virtual field trip shows students the geologic features of Enchanted Rock, a dome of Precambrian granite located in central Texas. They can see small faults, fault gouge, close-up photos showing the texture of the granite, and a variety of features produced by weathering. Full description.