Earth Revealed: Introductory Geology, originally titled Earth Revealed, is a 26-part video instructional series covering the processes and properties of the physical
Earth, with particular attention given to the scientific theories underlying
geological principles. The telecourse was produced by
Intelecom and the
Southern California Consortium, was funded by the
Annenberg/CPB Project, and first aired on
PBS in 1992 with the title Earth Revealed. All 26 episodes are hosted by Dr. James L. Sadd, professor of
environmental science at
Occidental College in
Los Angeles,
California.
Some footage used in Earth Revealed previously had been seen in the 1986 PBS series Planet Earth.
Module II: Plate Tectonics: The Unifying Model (March 2, 1992-April 13, 1992)
3. "Earth's Interior" – The episode introduces
geophysics, discussing how geophysicists study what lies beneath Earth's surface, using studies of
seismic waves, variations in temperature,
magnetic fields,
gravity, and computer simulations to create models of structures deep in the earth. The episode also discusses
paleomagnetism and the phenomenon of
magnetic field reversals.
4. "The Sea Floor" – The episode explains how geologists study the sea bottom, using research
submersibles and indirect methods, getting glimpses of volcanic activity; underwater formations such as the
continental shelf,
continental rise, slopes,
canyons,
abyssal plains, and
mid-ocean ridges; and life forms that thrive at extreme depths in a world of intense pressure and total darkness. The episode examines
subduction,
seafloor spreading,
hydrothermal vents, and the metallic resources found on the ocean bottom.
5. "The Birth of a Theory" – The episode examines the theory of
plate tectonics and its development from its beginnings in the work of
Alfred Wegener in the early 20th century through its maturation and acceptance in the 1960s. Topics covered include the prehistoric supercontinent
Pangaea,
continental drift, seafloor spreading, subduction trenches, paleomagnetism and magnetic field reversals,
transform faults, and
mantle convection.
7. "Mountain Building and the Growth of Continents" – The episode discusses the process of
orogeny (mountain building) and the role plate tectonics play in it,
cratons and their formation, the growth of continents through
accretion, the
erosion of mountains,
isostasy, how different types of rock form in the course of orogeny, and how rock types change over time through the
rock cycle.
9. "Earthquakes" – The episode discusses the forces that create
earthquakes, explaining
faults,
seismic waves, the transfer of energy from an earthquake's
epicenter, the method of determining an epicenter's exact location, how seismic waves affect different buildings differently, and the histories of the
seismograph and
Richter scale. It also describes devices under development in 1992 to study earthquakes with an eventual goal of predicting them.
Module III: Geologic Time and Life (April 20–27, 1992)
14. "Intrusive Igneous Rocks' – The episode examines the process in which
magma seeps into crevices in existing rock and cools to form
dikes of intrusive igneous rock without ever extruding onto the Earth's surface and how
plate tectonics play a role in the process. It also discusses the formation and types of magma,
xenoliths,
batholiths,
igneous differentiation, and how an understanding of igneous rock helps geologists understand the Earth's history. Geologists explain the types and textures of intrusive igneous rocks such as
granite,
obsidian, and
quartz.
16. "Mass Wasting" – The episode explains the phenomenon of
mass wasting — the downslope movement of earth under the influence of
gravity. It discusses various factors involved in mass wasting, including the rock's effective strength and
pore spaces, and different types of mass wasting such as
creep,
slump, and
landslides, as well as
rockslides,
debris flows, and
mudflows. It explains the influence of slope angle, water and rain, and human activities such as the construction of buildings and roads, on mass wasting. It also explains how
engineering geologists assess
slope stability.
17. "Sedimentary Rocks: The Key to Past Environments" – The episode describes how exposed layers of
sedimentary rock allow scientists to discern the Earth's geologic past, the movement of
sediment and its
deposition and how energy affects both transportation and deposition of sediments, how
weathering and
erosion influence the composition of sediments,
sorting, sedimentary
beds and
cross-bedding, and the production of sedimentary rocks through the processes of
lithification,
compaction, and
cementation. It also discusses organic components and the economic importance of sedimentary rocks.
Module V: Carving the Landscape (June 22, 1992-July 27, 1992)
19. "Running Water: Erosion and Deposition" – The episode discusses how
rivers play a vital role in the sculpting of land. It shows
landscapes formed by rivers, the various types of rivers, the basic parts of a river, and how the characteristics of rivers — their
slope,
channel, and
discharge — erode and build the surrounding terrain. The episode also covers
river bars,
meanders,
cut banks, aspects of
flooding including
floodplains, and the evolution of rivers.
20. "Running Water: Landscape Evolution" – The episode explains how rivers carve such features in the landscape as
canyons, discussing
erosion and
deposition processes as they relate to river characteristics and type of rock. It also discusses
base levels,
peneplains,
stream terraces,
incised meanders,
river deltas, stream rejuvenation, the evolution of rivers, and efforts to prevent consequences of river flow that are harmful to humans, such as
flood control efforts on the
Mississippi River.
24. "Waves, Beaches and Coasts" – The episode discusses the dynamic interaction of rocky landmasses and the energy of the
ocean, describing the types, parts, sources of energy, movement, and impact on the shore of
waves. It also covers
shoreline characteristics,
refraction,
currents, sea barriers,
tides,
tsunamis, how
dams affect
beach erosion, how the
greenhouse effect could affect
sea level and coastal lands, and the role of geologists in protecting the coastline.
Module VI: Living With Earth (August 3–10, 1992)
25. "Living With Earth: The Loma Prieta Earthquake" – The episode uses the 1989
Loma Prieta earthquake in
California as the starting point for a discussion of how humans are learning to cope with
earthquakes, methods of studying earthquakes, and how various groups and agencies are studying the
San Andreas Fault and the damage caused along its path during the Loma Prieta earthquake to better understand how earthquakes affect the land, buildings, and people. It also discusses
aftershocks,
liquefaction, scientific concerns about the
Hayward Fault, the cause of most human casualties during earthquakes, and what can be done to limit casualties and property damage in the event of an earthquake.
26. "Living With Earth: Preserving the Legacy" – The episode discusses the impact on the Earth of the
Industrial Revolution, as well as where
petroleum comes from, how it is discovered and extracted, and how it is converted into energy, and the effects on the Earth of
oil drilling and the burning of
fossil fuels. It also examines the potential of
alternative energy sources, including the pros and cons of, and problems related to, the exploitation of
geothermal energy.
Earth Revealed: Introductory Geology, originally titled Earth Revealed, is a 26-part video instructional series covering the processes and properties of the physical
Earth, with particular attention given to the scientific theories underlying
geological principles. The telecourse was produced by
Intelecom and the
Southern California Consortium, was funded by the
Annenberg/CPB Project, and first aired on
PBS in 1992 with the title Earth Revealed. All 26 episodes are hosted by Dr. James L. Sadd, professor of
environmental science at
Occidental College in
Los Angeles,
California.
Some footage used in Earth Revealed previously had been seen in the 1986 PBS series Planet Earth.
Module II: Plate Tectonics: The Unifying Model (March 2, 1992-April 13, 1992)
3. "Earth's Interior" – The episode introduces
geophysics, discussing how geophysicists study what lies beneath Earth's surface, using studies of
seismic waves, variations in temperature,
magnetic fields,
gravity, and computer simulations to create models of structures deep in the earth. The episode also discusses
paleomagnetism and the phenomenon of
magnetic field reversals.
4. "The Sea Floor" – The episode explains how geologists study the sea bottom, using research
submersibles and indirect methods, getting glimpses of volcanic activity; underwater formations such as the
continental shelf,
continental rise, slopes,
canyons,
abyssal plains, and
mid-ocean ridges; and life forms that thrive at extreme depths in a world of intense pressure and total darkness. The episode examines
subduction,
seafloor spreading,
hydrothermal vents, and the metallic resources found on the ocean bottom.
5. "The Birth of a Theory" – The episode examines the theory of
plate tectonics and its development from its beginnings in the work of
Alfred Wegener in the early 20th century through its maturation and acceptance in the 1960s. Topics covered include the prehistoric supercontinent
Pangaea,
continental drift, seafloor spreading, subduction trenches, paleomagnetism and magnetic field reversals,
transform faults, and
mantle convection.
7. "Mountain Building and the Growth of Continents" – The episode discusses the process of
orogeny (mountain building) and the role plate tectonics play in it,
cratons and their formation, the growth of continents through
accretion, the
erosion of mountains,
isostasy, how different types of rock form in the course of orogeny, and how rock types change over time through the
rock cycle.
9. "Earthquakes" – The episode discusses the forces that create
earthquakes, explaining
faults,
seismic waves, the transfer of energy from an earthquake's
epicenter, the method of determining an epicenter's exact location, how seismic waves affect different buildings differently, and the histories of the
seismograph and
Richter scale. It also describes devices under development in 1992 to study earthquakes with an eventual goal of predicting them.
Module III: Geologic Time and Life (April 20–27, 1992)
14. "Intrusive Igneous Rocks' – The episode examines the process in which
magma seeps into crevices in existing rock and cools to form
dikes of intrusive igneous rock without ever extruding onto the Earth's surface and how
plate tectonics play a role in the process. It also discusses the formation and types of magma,
xenoliths,
batholiths,
igneous differentiation, and how an understanding of igneous rock helps geologists understand the Earth's history. Geologists explain the types and textures of intrusive igneous rocks such as
granite,
obsidian, and
quartz.
16. "Mass Wasting" – The episode explains the phenomenon of
mass wasting — the downslope movement of earth under the influence of
gravity. It discusses various factors involved in mass wasting, including the rock's effective strength and
pore spaces, and different types of mass wasting such as
creep,
slump, and
landslides, as well as
rockslides,
debris flows, and
mudflows. It explains the influence of slope angle, water and rain, and human activities such as the construction of buildings and roads, on mass wasting. It also explains how
engineering geologists assess
slope stability.
17. "Sedimentary Rocks: The Key to Past Environments" – The episode describes how exposed layers of
sedimentary rock allow scientists to discern the Earth's geologic past, the movement of
sediment and its
deposition and how energy affects both transportation and deposition of sediments, how
weathering and
erosion influence the composition of sediments,
sorting, sedimentary
beds and
cross-bedding, and the production of sedimentary rocks through the processes of
lithification,
compaction, and
cementation. It also discusses organic components and the economic importance of sedimentary rocks.
Module V: Carving the Landscape (June 22, 1992-July 27, 1992)
19. "Running Water: Erosion and Deposition" – The episode discusses how
rivers play a vital role in the sculpting of land. It shows
landscapes formed by rivers, the various types of rivers, the basic parts of a river, and how the characteristics of rivers — their
slope,
channel, and
discharge — erode and build the surrounding terrain. The episode also covers
river bars,
meanders,
cut banks, aspects of
flooding including
floodplains, and the evolution of rivers.
20. "Running Water: Landscape Evolution" – The episode explains how rivers carve such features in the landscape as
canyons, discussing
erosion and
deposition processes as they relate to river characteristics and type of rock. It also discusses
base levels,
peneplains,
stream terraces,
incised meanders,
river deltas, stream rejuvenation, the evolution of rivers, and efforts to prevent consequences of river flow that are harmful to humans, such as
flood control efforts on the
Mississippi River.
24. "Waves, Beaches and Coasts" – The episode discusses the dynamic interaction of rocky landmasses and the energy of the
ocean, describing the types, parts, sources of energy, movement, and impact on the shore of
waves. It also covers
shoreline characteristics,
refraction,
currents, sea barriers,
tides,
tsunamis, how
dams affect
beach erosion, how the
greenhouse effect could affect
sea level and coastal lands, and the role of geologists in protecting the coastline.
Module VI: Living With Earth (August 3–10, 1992)
25. "Living With Earth: The Loma Prieta Earthquake" – The episode uses the 1989
Loma Prieta earthquake in
California as the starting point for a discussion of how humans are learning to cope with
earthquakes, methods of studying earthquakes, and how various groups and agencies are studying the
San Andreas Fault and the damage caused along its path during the Loma Prieta earthquake to better understand how earthquakes affect the land, buildings, and people. It also discusses
aftershocks,
liquefaction, scientific concerns about the
Hayward Fault, the cause of most human casualties during earthquakes, and what can be done to limit casualties and property damage in the event of an earthquake.
26. "Living With Earth: Preserving the Legacy" – The episode discusses the impact on the Earth of the
Industrial Revolution, as well as where
petroleum comes from, how it is discovered and extracted, and how it is converted into energy, and the effects on the Earth of
oil drilling and the burning of
fossil fuels. It also examines the potential of
alternative energy sources, including the pros and cons of, and problems related to, the exploitation of
geothermal energy.