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)

Contains the second of three columns reviewing films on earthquakes. The films are about earthquakes in general, though California earthquakes play a dominant role in many of these films, which are rated on a scale of one to five stars. The list includes the year made, length of time in minutes, distribution source, and price. One of the top-rated…

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)

Reviews current ideas and research findings related to the flow patterns of mantle rocks. Highlights the components of the two-layer convection and whole-mantle models of mantle flow. Proposes that mantle flow is the key to understanding how the earth has cooled and chemically evolved. (ML)

Presents a procedure for calculating the compass direction and velocity of present plate motions at any geographical point of interest. Includes a table of the relative and geographic motion of the 11 largest plates and a flow chart for determining their present motion. Also offers suggestions for classroom instruction. (ML)

Science writing from periods of great change in science can be used productively in the classroom to advance scientific literacy. Compares the scientific monograph with the short paper prevalent in the late 20th century and suggests that there are cases in which a small group of papers can serve the same function as a monograph. (Contains 30…

Presents fault activity with an emphasis on earthquakes and changes in continent shapes. Identifies three types of fault movement: normal, reverse, and strike faults. Discusses the seismic gap theory, plate tectonics, and the principle of superposition. Vignettes portray fault movement, and the locations of the San Andreas fault and epicenters of…

Considers the interface of humans and seacoasts over time. Explains how coastal zones are formed and human attempts to defend against sea level changes. Charts the percentage of major world cities that also are ports. Postulates how the greenhouse effect could influence sea level, examining potential human responses to changes in coastal zones.…

The authors relate that they have conducted short courses on using constructivist techniques to teach historical geology over the past four years at regional National Science Teachers Association (NSTA) meetings. They realized that although most course participants were familiar with the basic tenets of plate tectonics, the authors were always…

Reviews seismological studies that provide evidence of the existence of continental roots beneath the continents. Suggests, that through the collisions of plate tectonics, continents stabilized part of the mobile mantle rock beneath them to form deep roots. (ML)

Reviews various topics and research studies on the geology of volcanoes. Areas examined include volcanoes and weather, plate margins, origins of magma, magma evolution, United States Geological Survey (USGS) volcano hazards program, USGS volcano observatories, volcanic gases, potassium-argon dating activities, and volcano monitoring strategies.…

Points out that large earthquakes can take place not only on faults that cut the earth's surface but also on blind faults under folded terrain. Describes four examples of fold earthquakes. Discusses the fold earthquakes using several diagrams and pictures. (YP)

Presents an activity in which students trace the movement of the continents over the past 600 million years to help them understand how the continents' size and position have changed over time. Includes map puzzle pieces. (MKR)

Describes a laboratory activity on plate tectonics which focuses on the connection between plate tectonics and the different types of volcanoes. Provides questions for discussion and includes suggestions for extending the activity. (ML)