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 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…

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)

Offers explanations on the origin of the North American Atlantic continental margin. Provides an analysis and illustrations of structural and strategraphic elements of cross sections of the Atlantic continental margin. Also explains the operations and applications of seismic-relection profiles in studying ocean areas. (ML)

Presents an outline of two sets of curricular materials that address the internal rock cycle and the internal energy of the earth in relation to plate tectonic theory. (Contains 31 references.) (DDR)

Describes and attempts to explain the sporadic devastating effects of the Northridge (California) Earthquake of January 17, 1994, as being the result of constructive interference from P and S earthquake waves. (MVL)

Geophysics is the application of physics, chemistry, and mathematics to the problems and processes of the earth, from its innermost core to its outermost environs in space. Fields within geophysics include the atmospheric sciences; geodesy; geomagnetism and paleomagnetism; hydrology; oceanography; planetology; seismology; solar-planetary…

Discusses some of the events leading to the development of the theory of plate tectonics. Describes how seismic, volcanic, and tectonic features observed at the surface of the planet are now seen as a consequence of intense internal activity, and makes suggestions about their further investigation. (TW)

Introduces a package of six interrelated units on plate tectonics and earthquakes. The Seismic Sleuths curriculum contains hands-on activities integrating math, earth science, and social studies. Units cover personal experience as well as the science of earthquakes while students also construct buildings to study earthquake resistance. One…

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)