Hot spots are isolated areas of geologic activity where volcanic eruptions, earthquakes, and upwelling currents occur far from plate boundaries. These mantle plumes are relatively stable and crustal plates drift over them. The nature and location of hot spots (with particular attention to the Hawaiian Islands and Iceland) are discussed. (DH)

Describes models which (1) illustrate spreading that varies in rate from place to place; (2) clearly show transform faults as arcs of small circles; and (3) illustrate what happens near a pole of rotation. The models are easy to construct and have been well received by students. (JN)

Describes how seismic tomography is used to analyze the waves produced by earthquakes. The information obtained from the procedure can then be used to map the earth's mantle in three dimensions. The resulting maps are then studied to determine such information as the convective flow that propels the crustal plates. (JN)

Described are concepts involved with the formation and actions of the Mid-Ocean Ridge. Sea-floor spreading, the magma supply model, discontinuities, off-axis structures, overlaps and deviation, and aquatic life are discussed. (CW)

Describes the three processes of folding in rocks: buckling, bending, and passive folding. Discusses how geometrical properties and strain distributions help to identify which processes produce natural folds, and also provides information about the mechanical properties of rocks, and the sense of shear in shear zones. (TW)

Discussed are some of the reasons for earthquakes which occur in stable crust away from familiar zones at the ends of tectonic plates. Crust stability and the reactivation of old faults are described using examples from India and Australia. (CW)

Describes a laboratory exercise testing the Vine-Matthews-Morley hypothesis of plate tectonics. Includes 14 questions with explanations using graphs and charts. Provides a historical account of the current plate tectonic and magnetic anomaly theory. (MVL)

Develops an exercise in which students use magnetic-profile data gathered in the South Pacific to test the Vine-Matthews-Morley hypothesis. Uses the Eltanin 19N and 20N profiles. Relates the exercise to 20 current geology texts. (MVL)

Describes how mylonite samples can be used to determine the sense of shear. Several sample collection techniques are presented. Criteria for shear sense determination are outlined and discussed so that they can be recognized and interpreted by students familiar with the use of a compass and a petrographic microscope. (TW)