These pages, from PBS Online, demonstrate how plate tectonics affect the Earth's surface. It includes a brief introduction to the four main boundary types (convergent, divergent, collisional, and transform), a series of pages with information about related people and discoveries, such as pioneer geologists Hess, Wegener, and Holmes, and an interactive activity illustrating plate movement. Full description.

In this activity, students simulate deformational effects on Earth's crust using peanut butter and jelly sandwiches. These common sandwich components are used to model geologic features such as synclines, anticlines, and monoclines, and to demonstrate the effects of stresses and strains. Full description.

Available on this site is a host of images, maps, and animations derived from bathymetric and topographic data. Static images and maps include those of estimated seafloor topography from satellite altimetry, total sediment thickness of the ocean floor, Great Lakes bathymetry, world crustal ages, and coastal relief. Of particular note is an interactive surface map of the Earth, which is composed of ... Full description.

This article discusses the idea of 'hot spot' volcanoes, those not associated with plate tectonic boundaries, but rather with relatively stationary sources of heat energy (thermal plumes) in the mantle. Topics include the development of the theory by Canadian geophysicist J. Tuzo Wilson; the mechanics of volcanism over a hot spot as seen in the Hawaiian Islands; ancient Hawaiian observations of the ... Full description.

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.