''Earth Revealed: Introductory Geology'', originally titled ''Earth Revealed'', is a 26-part video instructional series covering the processes and properties of the physical

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

, with particular attention given to the scientific theories underlying

geological Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth s ...

principles. The telecourse was produced by Intelecom and the Southern California Consortium, was funded by the Annenberg/CPB Project, and first aired on

PBS The Public Broadcasting Service (PBS) is an American public broadcaster and non-commercial, free-to-air television network based in Arlington, Virginia. PBS is a publicly funded nonprofit organization and the most prominent provider of educat ...

in 1992 with the title ''Earth Revealed''. All 26 episodes are hosted by Dr. James L. Sadd, professor of environmental science at

Occidental College Occidental College (informally Oxy) is a private liberal arts college in Los Angeles, California, United States. Founded in 1887 as a coeducational college by clergy and members of the Presbyterian Church, it became non-sectarian in 1910. It is ...

Los Angeles Los Angeles, often referred to by its initials L.A., is the List of municipalities in California, most populous city in the U.S. state of California, and the commercial, Financial District, Los Angeles, financial, and Culture of Los Angeles, ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. Some footage used in ''Earth Revealed'' previously had been seen in the 1986 PBS series ''

Planet Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all of Earth's water is ...

''.

Episodes

Module I: Introduction (February 17–24, 1992)

:1. "Down to Earth" – Beginning by comparing surface conditions on the planets

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

and

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

with the living landscapes of the

to highlight how unique the Earth is, the episode describes the goal of the study of

geology Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth ...

and introduces major topics the series addresses, including the Earth's

heat engine A heat engine is a system that transfers thermal energy to do mechanical or electrical work. While originally conceived in the context of mechanical energy, the concept of the heat engine has been applied to various other kinds of energy, pa ...

plate tectonics Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed durin ...

volcanism Volcanism, vulcanism, volcanicity, or volcanic activity is the phenomenon where solids, liquids, gases, and their mixtures erupt to the surface of a solid-surface astronomical body such as a planet or a moon. It is caused by the presence of a he ...

earthquakes An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they c ...

and

seismology Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes (or generally, quakes) and the generation and propagation of elastic ...

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

, and

natural resources Natural resources are resources that are drawn from nature and used with few modifications. This includes the sources of valued characteristics such as commercial and industrial use, aesthetic value, scientific interest, and cultural value. ...

such as

groundwater Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit ...

. :2. "The Restless Planet" – The episode discusses the development of astronomical theory, including the

geocentrist In astronomy, the geocentric model (also known as geocentrism, often exemplified specifically by the Ptolemaic system) is a superseded description of the Universe with Earth at the center. Under most geocentric models, the Sun, Moon, stars, an ...

views of astronomers in

ancient Greece Ancient Greece () was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity (), that comprised a loose collection of culturally and linguistically r ...

and the discoveries of

Copernicus Nicolaus Copernicus (19 February 1473 – 24 May 1543) was a Renaissance polymath who formulated a mathematical model, model of Celestial spheres#Renaissance, the universe that placed heliocentrism, the Sun rather than Earth at its cen ...

Galileo Galilei Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei ( , , ) or mononymously as Galileo, was an Italian astronomer, physicist and engineer, sometimes described as a poly ...

Johannes Kepler Johannes Kepler (27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, Natural philosophy, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best know ...

, and

Isaac Newton Sir Isaac Newton () was an English polymath active as a mathematician, physicist, astronomer, alchemist, theologian, and author. Newton was a key figure in the Scientific Revolution and the Age of Enlightenment, Enlightenment that followed ...

. It also describes the formation of the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

and the physical evolution of the Earth over time, including its internal structure – through the process of

planetary differentiation In planetary science, planetary differentiation is the process by which the chemical elements of a planetary body accumulate in different areas of that body, due to their physical or chemical behavior (e.g. density and chemical affinities). The pr ...

– and development and retention of an internal heat engine, its

atmosphere An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...

, its

hydrosphere The hydrosphere () is the combined mass of water found on, under, and above the Planetary surface, surface of a planet, minor planet, or natural satellite. Although Earth's hydrosphere has been around for about 4 billion years, it continues to ch ...

, and the appearance of life.

Module II: Plate Tectonics: The Unifying Model (March 2, 1992-April 13, 1992)

:3. "Earth's Interior" – The episode introduces

geophysics Geophysics () is a subject of natural science concerned with the physical processes and Physical property, properties of Earth and its surrounding space environment, and the use of quantitative methods for their analysis. Geophysicists conduct i ...

, discussing how geophysicists study what lies beneath Earth's surface, using studies of

seismic wave A seismic wave is a mechanical wave of acoustic energy that travels through the Earth or another planetary body. It can result from an earthquake (or generally, a quake), volcanic eruption, magma movement, a large landslide and a large ma ...

s, variations in temperature,

magnetic field A magnetic field (sometimes called B-field) is a physical field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular ...

gravity In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force b ...

, and computer simulations to create models of structures deep in the earth. The episode also discusses

paleomagnetism Paleomagnetism (occasionally palaeomagnetism) is the study of prehistoric Earth's magnetic fields recorded in rocks, sediment, or archeological materials. Geophysicists who specialize in paleomagnetism are called ''paleomagnetists.'' Certain ...

and the phenomenon of magnetic field reversals. :4. "The Sea Floor" – The episode explains how geologists study the sea bottom, using research

submersible A submersible is an underwater vehicle which needs to be transported and supported by a larger ship, watercraft or dock, platform. This distinguishes submersibles from submarines, which are self-supporting and capable of prolonged independent ope ...

s and indirect methods, getting glimpses of volcanic activity; underwater formations such as the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an islan ...

continental rise The continental rise is a low-relief zone of accumulated sediments that lies between the continental slope and the abyssal plain. It is a major part of the continental margin, covering around 10% of the ocean floor. Formation This geologic s ...

, slopes,

canyon A canyon (; archaic British English spelling: ''cañon''), gorge or chasm, is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic time scales. Rivers have a natural tendency t ...

abyssal plain An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between . Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth's surface. They ...

s, 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 Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

seafloor spreading Seafloor spreading, or seafloor spread, is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. History of study Earlier theories by Alfred Wegener ...

hydrothermal vent Hydrothermal vents are fissures on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hot ...

s, and the metallic resources found on the ocean bottom. :5. "The Birth of a Theory" – The episode examines the theory of

and its development from its beginnings in the work of

Alfred Wegener Alfred Lothar Wegener (; ; 1 November 1880 – November 1930) was a German climatologist, geologist, geophysicist, meteorologist, and polar researcher. During his lifetime he was primarily known for his achievements in meteorology and ...

in the early 20th century through its maturation and acceptance in the 1960s. Topics covered include the prehistoric supercontinent

Pangaea Pangaea or Pangea ( ) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous period approximately 335 mi ...

continental drift Continental drift is a highly supported scientific theory, originating in the early 20th century, that Earth's continents move or drift relative to each other over geologic time. The theory of continental drift has since been validated and inc ...

, seafloor spreading, subduction trenches, paleomagnetism and magnetic field reversals,

transform fault A transform fault or transform boundary, is a fault (geology), fault along a plate boundary where the motion (physics), motion is predominantly Horizontal plane, horizontal. It ends abruptly where it connects to another plate boundary, either an ...

s, and

mantle convection Mantle convection is the very slow creep of Earth's solid silicate mantle as convection currents carry heat from the interior to the planet's surface. Mantle convection causes tectonic plates to move around the Earth's surface. The Earth's l ...

. :6. "Plate Dynamics" – The episode examines the movement and interaction of

tectonic plate Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed durin ...

s and discusses the many geologic formations and phenomena that result from it, including faults,

rift valley A rift valley is a linear shaped lowland between several highlands or mountain ranges produced by the action of a geologic rift. Rifts are formed as a result of the pulling apart of the lithosphere due to extensional tectonics. The linear ...

convergent plate boundaries A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a ...

, divergent plate boundaries,

, subduction, and

hotspots Hotspot, Hot Spot or Hot spot may refer to: Places * Hot Spot, Kentucky, a community in the United States Arts, entertainment, and media Fictional entities * Hot Spot (comics), a name for the DC Comics character Isaiah Crockett * Hot Spot (Tr ...

. It also discusses the

lithosphere A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the lithospheric mantle, the topmost portion of the upper mantle that behaves elastically on time ...

and

asthenosphere The asthenosphere () is the mechanically weak and ductile region of the upper mantle of Earth. It lies below the lithosphere, at a depth between c. below the surface, and extends as deep as . However, the lower boundary of the asthenosphere i ...

and how they interact,

mantle plume A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic ho ...

s, and the debate among geologists over what drives the motion of plates. :7. "Mountain Building and the Growth of Continents" – The episode discusses the process of

orogeny Orogeny () is a mountain-mountain formation, building process that takes place at a convergent boundary, convergent plate margin when plate motion compresses the margin. An or develops as the compressed plate crumples and is tectonic uplift, u ...

(mountain building) and the role plate tectonics play in it,

craton A craton ( , , or ; from "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging and rifting of contine ...

s and their formation, the growth of continents through

accretion Accretion may refer to: Science * Accretion (astrophysics), the formation of planets and other bodies by collection of material through gravity * Accretion (meteorology), the process by which water vapor in clouds forms water droplets around nucl ...

, the

of mountains,

isostasy Isostasy (Greek wikt:ἴσος, ''ísos'' 'equal', wikt:στάσις, ''stásis'' 'standstill') or isostatic equilibrium is the state of gravity, gravitational mechanical equilibrium, equilibrium between Earth's crust (geology), crust (or lithosph ...

, how different types of rock form in the course of orogeny, and how rock types change over time through the

rock cycle The ''rock cycle'' is a basic concept in geology that describes transitions through geologic time among the three main rock types: sedimentary, metamorphic, and igneous. Each rock type is altered when it is forced out of its equilibrium cond ...

. :8. "Earth's Structures" – The episode explores

rock layers Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wales ...

outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth and other terrestrial planets. Features Outcrops do not cover the majority of the Earth's land surface because in most p ...

s and geologic cross-sections,

sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to th ...

and sedimentary layering, the

principle of original horizontality The principle of original horizontality states that layers of sediment are originally deposited horizontally under the action of gravity. It is a relative dating technique. The principle is important to the analysis of folded and tilted strata. ...

, major structures of rocks – including

fractures Fracture is the appearance of a crack or complete separation of an object or material into two or more pieces under the action of stress (mechanics), stress. The fracture of a solid usually occurs due to the development of certain displacemen ...

joints A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw- ...

, faults, folds,

anticline In structural geology, an anticline is a type of Fold (geology), fold that is an arch-like shape and has its oldest Bed (geology), beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex curve, c ...

syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimposed ...

s, and uncomformities – and the methods used to study them. It also examines tectonic force and the different types of stress involved in the formation of geologic structures and the deformation of rocks. Finally, it describes how geologic structures can trap

petroleum Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring un ...

natural gas Natural gas (also fossil gas, methane gas, and gas) is a naturally occurring compound of gaseous hydrocarbons, primarily methane (95%), small amounts of higher alkanes, and traces of carbon dioxide and nitrogen, hydrogen sulfide and helium ...

, and

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

and the resulting importance of the study of geologic structures in

economic geology Economic geology is concerned with earth materials that can be used for economic and industrial purposes. These materials include precious and base metals, nonmetallic minerals and dimension stone, construction-grade stone. Economic geology is a ...

. :9. "Earthquakes" – The episode discusses the forces that create

earthquake An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...

s, explaining faults,

s, the transfer of energy from an earthquake's

epicenter The epicenter (), epicentre, or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Determination The primary purpose of a ...

, the method of determining an epicenter's exact location, how seismic waves affect different buildings differently, and the histories of the

seismograph A seismometer is an instrument that responds to ground displacement and shaking such as caused by quakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The out ...

and

Richter scale The Richter scale (), also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale, is a measure of the strength of earthquakes, developed by Charles Richter in collaboration with Beno Gutenberg, and pr ...

. 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)

:10. "Geologic Time" – The episode describes the immensity of

geologic time The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronolo ...

, the timeline of major geologic events in the Earth's history, the relationship between the geologic timeline and the history of life on Earth, and the use of

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

radiocarbon dating Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for Chronological dating, determining the age of an object containing organic material by using the properties of carbon-14, radiocarbon, a radioactive Isotop ...

, and

uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...

radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to Chronological dating, date materials such as Rock (geology), rocks or carbon, in which trace radioactive impurity, impurities were selectively incorporat ...

to determine the age of rocks, fossils, and the Earth itself. The episode highlights the contributions of

James Hutton James Hutton (; 3 June Old Style and New Style dates, O.S. 1726 – 26 March 1797) was a Scottish geologist, Agricultural science, agriculturalist, chemist, chemical manufacturer, Natural history, naturalist and physician. Often referred to a ...

and

Ernest Rutherford Ernest Rutherford, 1st Baron Rutherford of Nelson (30 August 1871 – 19 October 1937) was a New Zealand physicist who was a pioneering researcher in both Atomic physics, atomic and nuclear physics. He has been described as "the father of nu ...

and discusses

unconformities An unconformity is a buried erosion surface, erosional or non-depositional surface separating two Rock (geology), rock masses or Stratum, strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer ...

uniformitarianism Uniformitarianism, also known as the Doctrine of Uniformity or the Uniformitarian Principle, is the assumption that the same natural laws and processes that operate in our present-day scientific observations have always operated in the universe in ...

, the

law of superposition The law of superposition is an axiom that forms one of the bases of the sciences of geology, archaeology, and other fields pertaining to geological stratigraphy. In its plainest form, it states that in undeformed stratigraphic sequences, the ...

, the

cross-cutting relationships Cross-cutting relationships is a principle of geology that states that the geologic feature which cuts another is the younger of the two features. It is a relative dating technique in geology. It was first developed by Danish geological pioneer ...

, relative age dating, and

paleontology Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure ge ...

. :11. "Evolution Through Time" – The episode focuses on how the

record reveals the diversity and development of life on Earth, examining the traces left by single-celled

prokaryote A prokaryote (; less commonly spelled procaryote) is a unicellular organism, single-celled organism whose cell (biology), cell lacks a cell nucleus, nucleus and other membrane-bound organelles. The word ''prokaryote'' comes from the Ancient Gree ...

s and

eukaryote The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms ...

s, early

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

animal Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, ...

s, and the progression of life forms over time through the " Cambrian explosion" and the

Paleozoic The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

, and

Cenozoic The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...

eras, as well as the fossils found at the

La Brea Tar Pits La Brea Tar Pits comprise an active Paleontological site, paleontological research site in urban Los Angeles. Hancock Park was formed around a group of tar pits where natural Bitumen, asphalt (also called asphaltum, bitumen, or pitch; ''brea'' ...

; and the

theory of evolution Evolution is the change in the heritable characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, resulting in certai ...

. The episode discusses the connections between life on Earth and

atmospheric gases The atmosphere of Earth is composed of a layer of gas mixture that surrounds the Earth's planetary surface (both lands and oceans), known collectively as air, with variable quantities of suspended aerosols and particulates (which create weather ...

climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

, and the formation of rocks, as well as biological functions,

mass extinction An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp fall in the diversity and abundance of multicellular organisms. It occ ...

s, and the effects humans have had on the

biosphere The biosphere (), also called the ecosphere (), is the worldwide sum of all ecosystems. It can also be termed the zone of life on the Earth. The biosphere (which is technically a spherical shell) is virtually a closed system with regard to mat ...

Module IV: The Rock Cycle (May 4, 1992-June 15, 1992)

:12. "Minerals: The Materials of Earth" – The episode examines the variety of

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...

s, their

atom Atoms are the basic particles of the chemical elements. An atom consists of a atomic nucleus, nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished fr ...

ic and

crystalline structure In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystalline material. Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that repeat ...

s, and their physical properties such as color,

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to plastic deformation, such as an indentation (over an area) or a scratch (linear), induced mechanically either by Pressing (metalworking), pressing or abrasion ...

, luster,

cleavage Cleavage may refer to: Science * Cleavage (crystal), the way in which a crystal or mineral tends to split * Cleavage (embryo), the division of cells in an early embryo * Cleavage (geology), foliation of rock perpendicular to stress, a result of ...

, and streak. It also describes how petrologists section rocks and discusses hydrothermal solutions, the precipitation of

metal A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, electricity and thermal conductivity, heat relatively well. These properties are all associated wit ...

lic minerals,

gem A gemstone (also called a fine gem, jewel, precious stone, semiprecious stone, or simply gem) is a piece of mineral crystal which, when cut or polished, is used to make jewelry or other adornments. Certain rocks (such as lapis lazuli, opal, an ...

precious metal Precious metals are rare, naturally occurring metallic chemical elements of high Value (economics), economic value. Precious metals, particularly the noble metals, are more corrosion resistant and less reactivity (chemistry), chemically reac ...

s, the formation and excavation of

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically including metals, concentrated above background levels, and that is economically viable to mine and process. The grade of ore refers to the concentration ...

s, and the value of

silicate A silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula , where . The family includes orthosilicate (), metasilicate (), and pyrosilicate (, ). The name is also used ...

s. :13. "Volcanism" – The episode describes volcanic processes, how

boundaries are related to

, and how

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

es provide geologists with clues as to what is happening within the Earth. It also surveys the various types of

volcanic eruptions A volcanic eruption occurs when material is expelled from a volcanic vent or fissure. Several types of volcanic eruptions have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior h ...

, craters,

cones In geometry, a cone is a three-dimensional figure that tapers smoothly from a flat base (typically a circle) to a point not contained in the base, called the ''apex'' or '' vertex''. A cone is formed by a set of line segments, half-lines, ...

, and vents,

lava dome In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions ...

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...

rift zone A rift zone is a feature of some volcanoes, especially shield volcanoes, in which a set of linear cracks (or rifts) develops in a volcanic edifice, typically forming into two or three well-defined regions along the flanks of the vent. Believed ...

volcanic rock Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and me ...

, the relationship of volcanoes to

deposits and

geothermal energy Geothermal energy is thermal energy extracted from the crust (geology), crust. It combines energy from the formation of the planet and from radioactive decay. Geothermal energy has been exploited as a source of heat and/or electric power for m ...

, and the clues that

volcanologist A volcanologist, or volcano scientist, is a geologist who focuses on understanding the formation and eruptive activity of volcanoes. Volcanologists frequently visit volcanoes, sometimes active ones, to observe and monitor volcanic eruptions, col ...

s use to predict eruptions. :14. "Intrusive Igneous Rocks' – The episode examines the process in which

seeps into crevices in existing rock and cools to form

dikes Dyke or dike may refer to: General uses * Dyke (slang), a slang word meaning "lesbian" * Dike (geology), formations of magma or sediment that cut through and across the layering of adjacent rocks * Dike (mythology), ''Dikē'', the Greek goddess ...

of intrusive igneous rock without ever extruding onto the Earth's surface and how

play a role in the process. It also discusses the formation and types of magma,

xenolith A xenolith ("foreign rock") is a rock (geology), rock fragment (Country rock (geology), country rock) that becomes enveloped in a larger rock during the latter's development and solidification. In geology, the term ''xenolith'' is almost exclusi ...

batholith A batholith () is a large mass of intrusive rock, intrusive igneous rock (also called plutonic rock), larger than in area, that forms from cooled magma deep in the Earth's crust. Batholiths are almost always made mostly of felsic or intermediate ...

igneous differentiation In geology, igneous differentiation, or magmatic differentiation, is an umbrella term for the various processes by which magmas undergo bulk chemical change during the partial melting process, cooling, emplacement, or eruption. The sequence of ...

, 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 Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

obsidian Obsidian ( ) is a naturally occurring volcanic glass formed when lava extrusive rock, extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. Produced from felsic lava, obsidian is rich in the lighter element ...

, and

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

. :15. "Weathering and Soils" – This episode shows how

weather Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloud cover, cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmo ...

climate Climate is the long-term weather pattern in a region, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteoro ...

chemicals A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combin ...

temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...

, and type of substrate play a role in rock erosion and the formation of soil. It discusses mechanical and chemical

weathering Weathering is the deterioration of rocks, soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs '' in situ'' (on-site, with little or no move ...

of rocks, rock exfoliation and

fracturing Fracture is the appearance of a crack or complete separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity sur ...

, the acidification of rainwater and formation of

acid rain Acid rain is rain or any other form of Precipitation (meteorology), precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). Most water, including drinking water, has a neutral pH that exists b ...

soil horizon A soil horizon is a layer parallel to the soil surface whose physical, chemical and biological characteristics differ from the layers above and beneath. Horizons are defined in many cases by obvious physical features, mainly colour and texture. ...

s, the

Dust Bowl The Dust Bowl was a period of severe dust storms that greatly damaged the ecology and agriculture of the American and Canadian prairies during the 1930s. The phenomenon was caused by a combination of natural factors (severe drought) and hum ...

of the 1930s, the effect of

irrigation Irrigation (also referred to as watering of plants) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has bee ...

on soils,

windbreak A windbreak (shelterbelt) is a planting usually made up of one or more rows of trees or shrubs planted in such a manner as to provide shelter from the wind and to protect soil from erosion. They are commonly planted in hedgerows around the ed ...

s, and the importance of soil as a natural resource. It also shows how a

soil conservation Soil conservation is the prevention of loss of the topmost layer of the soil from erosion or prevention of reduced fertility caused by over usage, Soil acidification, acidification, salinization or other chemical soil contamination Slash-and-b ...

plan is developed and put into action at a farm in

Mojave Desert The Mojave Desert (; ; ) is a desert in the rain shadow of the southern Sierra Nevada mountains and Transverse Ranges in the Southwestern United States. Named for the Indigenous peoples of the Americas, indigenous Mohave people, it is located pr ...

. :16. "Mass Wasting" – The episode explains the phenomenon of

mass wasting Mass wasting, also known as mass movement, is a general term for the movement of rock (geology), rock or soil down slopes under the force of gravity. It differs from other processes of erosion in that the debris transported by mass wasting is no ...

— the downslope movement of earth under the influence of

. It discusses various factors involved in mass wasting, including the rock's effective strength and

pore Pore may refer to: Biology Animal biology and microbiology * Sweat pore, an anatomical structure of the skin of humans (and other mammals) used for secretion of sweat * Hair follicle, an anatomical structure of the skin of humans (and other ...

spaces, and different types of mass wasting such as

creep The Committee for the Re-election of the President (or the Committee to Re-elect the President, CRP, but often mocked by the acronym CREEP) was, officially, a fundraising organization of United States President Richard Nixon's 1972 re-election ...

, slump, and

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

s, as well as

rockslide A rockslide is a type of landslide caused by rock failure in which part of the bedding plane of failure passes through compacted rock and material collapses ''en masse'' and not in individual blocks. Note that a rockslide is similar to an ava ...

debris flow Debris flows are geological phenomena in which water-laden masses of soil and fragmented Rock (geology), rock flow down mountainsides, funnel into stream channels, entrain objects in their paths, and form thick, muddy deposits on valley floors. ...

s, and

mudflow A mudflow, also known as mudslide or mud flow, is a form of mass wasting involving fast-moving flow of debris and dirt that has become liquified by the addition of water. Such flows can move at speeds ranging from 3 meters/minute to 5 meters/se ...

s. 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 Engineering geology is the application of geology to engineering study for the purpose of assuring that the geological factors regarding the location, design, construction, operation and maintenance of engineering works are recognized and accou ...

assess

slope stability Slope stability refers to the condition of inclined soil or rock slopes to withstand or undergo movement; the opposite condition is called slope instability or slope failure. The stability condition of slopes is a subject of study and research i ...

. :17. "Sedimentary Rocks: The Key to Past Environments" – The episode describes how exposed layers of

sedimentary rock Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...

allow scientists to discern the Earth's geologic past, the movement of

sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

and its deposition and how energy affects both transportation and deposition of sediments, how

and

influence the composition of sediments,

sorting Sorting refers to ordering data in an increasing or decreasing manner according to some linear relationship among the data items. # ordering: arranging items in a sequence ordered by some criterion; # categorizing: grouping items with similar p ...

, sedimentary

beds A bed is a piece of furniture that is used as a place to sleep, rest, and relax. Most modern beds consist of a soft, cushioned mattress on a bed frame. The mattress rests either on a solid base, often wood slats, or a sprung base. Many be ...

and

cross-bedding In geology, cross-bedding, also known as cross-stratification, is layering within a stratum and at an angle to the main bedding plane. The sedimentary structures which result are roughly horizontal units composed of inclined layers. The origina ...

, and the production of sedimentary rocks through the processes of

lithification Lithification (from the Ancient Greek word ''lithos'' meaning 'rock' and the Latin-derived suffix ''-ific'') is the process in which sediments compact under pressure, expel connate fluids, and gradually become solid rock. Essentially, lithificati ...

, compaction, and cementation. It also discusses organic components and the economic importance of sedimentary rocks. :18. "Metamorphic Rocks" – The episode describes how the weight of a mountain creates enough pressure to recrystallize rock, thus creating

metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, caus ...

s. It outlines the recrystallization process and the types of rock it can create, including

claystone Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone and shale. Most of the particles of which the stone is composed are less than and are too small to ...

slate Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic ro ...

schist Schist ( ) is a medium-grained metamorphic rock generally derived from fine-grained sedimentary rock, like shale. It shows pronounced ''schistosity'' (named for the rock). This means that the rock is composed of mineral grains easily seen with a l ...

, and

garnet Garnets () are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. Garnet minerals, while sharing similar physical and crystallographic properties, exhibit a wide range of chemical compositions, de ...

-bearing

gneiss Gneiss (pronounced ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. This rock is formed under p ...

, and it explains the relationship of metamorphic rock to

. It also discusses

protolith A protolith () is the original, unmetamorphosed rock from which a given metamorphic rock is formed. For example, the protolith of a slate is a shale or mudstone. Metamorphic rocks can be derived from any other kind of non-metamorphic rock and ...

foliation In mathematics (differential geometry), a foliation is an equivalence relation on an topological manifold, ''n''-manifold, the equivalence classes being connected, injective function, injectively immersed submanifolds, all of the same dimension ...

migmatite Migmatite is a composite rock (geology), rock found in medium and high-grade metamorphic environments, commonly within Precambrian craton, cratonic blocks. It consists of two or more constituents often layered repetitively: one layer is an old ...

contact metamorphism Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of c ...

, and

regional metamorphism Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of che ...

Module V: Carving the Landscape (June 22, 1992-July 27, 1992)

:19. "Running Water: Erosion and Deposition" – The episode discusses how

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

s play a vital role in the sculpting of land. It shows

landscape A landscape is the visible features of an area of land, its landforms, and how they integrate with natural or human-made features, often considered in terms of their aesthetic appeal.''New Oxford American Dictionary''. A landscape includes th ...

s formed by rivers, the various types of rivers, the basic parts of a river, and how the characteristics of rivers — their

slope In mathematics, the slope or gradient of a Line (mathematics), line is a number that describes the direction (geometry), direction of the line on a plane (geometry), plane. Often denoted by the letter ''m'', slope is calculated as the ratio of t ...

channel Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Australia in Queensland and pa ...

, and discharge — erode and build the surrounding terrain. The episode also covers river bars,

meander A meander is one of a series of regular sinuous curves in the Channel (geography), channel of a river or other watercourse. It is produced as a watercourse erosion, erodes the sediments of an outer, concave bank (cut bank, cut bank or river cl ...

cut bank A cut bank, also known as a river cliff or river-cut cliff, is the outside bank of a curve (meander) in a water channel (stream), which is continually undergoing erosion.Essentials of Geology, 3rd Ed, Stephen Marshak Cut banks are found in ab ...

s, aspects of

flooding A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are of significant concern in agriculture, civi ...

including

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...

s, and the evolution of rivers. :20. "Running Water: Landscape Evolution" – The episode explains how rivers carve such features in the landscape as

s, discussing

and deposition processes as they relate to river characteristics and type of rock. It also discusses

base level In geology and geomorphology a base level is the lower limit for the vertical position of an erosion, erosion process. The modern term was introduced by John Wesley Powell in 1875. The term was subsequently appropriated by William Morris Davis wh ...

peneplain In geomorphology and geology, a peneplain is a low-relief plain formed by protracted erosion. This is the definition in the broadest of terms, albeit with frequency the usage of peneplain is meant to imply the representation of a near-final (or ...

stream terrace Fluvial terraces are elongated terraces that flank the sides of floodplains and fluvial valleys all over the world. They consist of a relatively level strip of land, called a "tread", separated from either an adjacent floodplain, other fluvial t ...

incised meander A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank or river cliff) and deposits sediments on an inn ...

river delta A river delta is a landform, archetypically triangular, created by the deposition of the sediments that are carried by the waters of a river, where the river merges with a body of slow-moving water or with a body of stagnant water. The creat ...

s, stream rejuvenation, the evolution of rivers, and efforts to prevent consequences of river flow that are harmful to humans, such as

flood control Flood management or flood control are methods used to reduce or prevent the detrimental effects of flood waters. Flooding can be caused by a mix of both natural processes, such as extreme weather upstream, and human changes to waterbodies and ru ...

efforts on the

Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...

. :21. "Groundwater" – The episode focuses on how most

fresh water Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salt (chemistry), salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include ...

comes from underground, making

an important natural resource. It discusses

aquifer An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The s ...

s and

aquiclude An aquifer is an underground layer of water-bearing material, consisting of permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The study of water flow in aquifers ...

s; rock

porosity Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure ...

and permeability; effluence;

artesian well An artesian well is a well that brings groundwater to the surface without pumping because it is under pressure within a body of rock or sediment known as an aquifer. When trapped water in an aquifer is surrounded by layers of Permeability (ea ...

s; the

water table The water table is the upper surface of the phreatic zone or zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with groundwater, which may be fresh, saline, or brackish, depending on the loc ...

; the formation of

cave Caves or caverns are natural voids under the Earth's Planetary surface, surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance undergrou ...

stalactite A stalactite (, ; , ) is a mineral formation that hangs from the ceiling of caves, hot springs, or man-made structures such as bridges and mines. Any material that is soluble and that can be deposited as a colloid, or is in suspension (chemistry ...

s, and

stalagmite A stalagmite (, ; ; ) is a type of rock formation that rises from the floor of a cave due to the accumulation of material deposited on the floor from ceiling drippings. Stalagmites are typically composed of calcium carbonate, but may consist ...

sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are also known as shakeholes, and to openings where surface water ...

s; ways in which groundwater can become contaminated; how groundwater is recharged naturally; and the role of

hydrogeology Hydrogeology (''hydro-'' meaning water, and ''-geology'' meaning the study of the Earth) is the area of geology that deals with the distribution and movement of groundwater in the soil and rock (geology), rocks of the Earth's crust (ge ...

in groundwater management. :22. "Wind, Dust and Deserts" – The episode shows how

desert A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the la ...

s are defined by infrequent

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwe ...

, where most deserts are located, and how

desertification Desertification is a type of gradual land degradation of Soil fertility, fertile land into arid desert due to a combination of natural processes and human activities. The immediate cause of desertification is the loss of most vegetation. This i ...

relates to proximity to the

equator The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumferen ...

, proximity to mountains, and ultimately

. It describes

alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to Semi-arid climate, semiar ...

s, interior drainage patterns of deserts,

desert pavement A desert pavement, also called reg (in western Sahara), serir (in eastern Sahara), gibber (in Australia), or saï (in central Asia) is a desert surface covered with closely packed, interlocking angular or rounded rock fragments of pebble and ...

, and

desert varnish Desert varnish or rock varnish is an orange-yellow to black coating found on exposed rock surfaces in arid environments. Desert varnish is approximately one micrometer thick and exhibits nanometer-scale layering. Rock rust and desert patina ar ...

; examines how

wind Wind is the natural movement of atmosphere of Earth, air or other gases relative to a planetary surface, planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heatin ...

transports

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

and creates

dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat ...

dry lake A dry lake bed, also known as a playa (), is a basin or depression that formerly contained a standing surface water body, which disappears when evaporation processes exceed recharge. If the floor of a dry lake is covered by deposits of alkalin ...

blowout Blowout or Blow out may refer to: Film and television *''Blow Out'', a 1981 film by Brian De Palma * '' The Blow Out'', a 1936 short film * ''Blow Out'' (TV series), a TV series on Bravo * "Blow Out" (''Prison Break''), an episode of ''Priso ...

s, and

oases In ecology, an oasis (; : oases ) is a fertile area of a desert or semi-desert environment glacier A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

s shape the

, explaining the formation, structure, and movement of glaciers and how they gouge and accumulate earth and rocks. It also describes basal slip, the

snow line The climatic snow line is the boundary between a snow-covered and snow-free surface. The actual snow line may adjust seasonally, and be either significantly higher in elevation, or lower. The permanent snow line is the level above which snow wil ...

glacial striation Glacial striations or striae are scratches or gouges cut into bedrock by glacial abrasion. These scratches and gouges were first recognized as the result of a moving glacier in the late 18th century when Swiss alpinists first associated them ...

till image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

, glacial

landform A landform is a land feature on the solid surface of the Earth or other planetary body. They may be natural or may be anthropogenic (caused or influenced by human activity). Landforms together make up a given terrain, and their arrangement ...

s such as

moraine A moraine is any accumulation of unconsolidated debris (regolith and Rock (geology), rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a gla ...

s, and how the study of glaciers may help us understand

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and g ...

s and the

greenhouse effect The greenhouse effect occurs when greenhouse gases in a planet's atmosphere insulate the planet from losing heat to space, raising its surface temperature. Surface heating can happen from an internal heat source (as in the case of Jupiter) or ...

. :24. "Waves, Beaches and Coasts" – The episode discusses the dynamic interaction of rocky landmasses and the energy of the

ocean The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as ''oceans'' (the Pacific, Atlantic, Indian Ocean, Indian, Southern Ocean ...

, describing the types, parts, sources of energy, movement, and impact on the shore of

wave In physics, mathematics, engineering, and related fields, a wave is a propagating dynamic disturbance (change from List of types of equilibrium, equilibrium) of one or more quantities. ''Periodic waves'' oscillate repeatedly about an equilibrium ...

s. It also covers

shoreline A coast (coastline, shoreline, seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, su ...

characteristics,

refraction In physics, refraction is the redirection of a wave as it passes from one transmission medium, medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commo ...

currents Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (hy ...

, sea barriers,

tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables ...

tsunami A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...

s, how

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aqua ...

s affect

beach erosion Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms. The landward r ...

, how the

could affect

sea level Mean sea level (MSL, often shortened to sea level) is an mean, average surface level of one or more among Earth's coastal Body of water, bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical ...

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 On October 17, 1989, at 5:04 p.m. PST, the Loma Prieta earthquake occurred at the Central Coast of California. The shock was centered in The Forest of Nisene Marks State Park in Santa Cruz County, approximately 10 mi (16 km) ...

as the starting point for a discussion of how humans are learning to cope with

s, methods of studying earthquakes, and how various groups and agencies are studying the

San Andreas Fault The San Andreas Fault is a continental Fault (geology)#Strike-slip faults, right-lateral strike-slip transform fault that extends roughly through the U.S. state of California. It forms part of the tectonics, tectonic boundary between the Paci ...

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

aftershock In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in Epicenter, the same area of the Mainshock, main shock, caused as the displaced Crust (geology), crust adjusts to the effects of the main shock. Large earthq ...

liquefaction In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics. It occurs both naturally and artificially. As an example of t ...

, scientific concerns about the

Hayward Fault The Hayward Fault Zone is a right-lateral strike-slip geologic fault zone capable of generating destructive earthquakes. The fault was first named in the Lawson Report of the 1906 San Francisco Earthquake in recognition of its involvement in the ...

, 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 The Industrial Revolution, sometimes divided into the First Industrial Revolution and Second Industrial Revolution, was a transitional period of the global economy toward more widespread, efficient and stable manufacturing processes, succee ...

, as well as where

comes from, how it is discovered and extracted, and how it is converted into energy, and the effects on the Earth of

oil drilling An oil well is a drillhole boring (earth), boring in Earth that is designed to bring petroleum oil hydrocarbons to the surface. Usually some natural gas is released as associated petroleum gas along with the oil. A well that is designed to produ ...

and the burning of

fossil fuel A fossil fuel is a flammable carbon compound- or hydrocarbon-containing material formed naturally in the Earth's crust from the buried remains of prehistoric organisms (animals, plants or microplanktons), a process that occurs within geolog ...

s. It also examines the potential of

alternative energy Renewable energy (also called green energy) is energy made from renewable resource, renewable natural resources that are replenished on a human lifetime, human timescale. The most widely used renewable energy types are solar energy, wind pow ...

sources, including the pros and cons of, and problems related to, the exploitation of

References

* * *

External links

* {{IMDb title, 1101167
Excerpt from ''Earth Revealed'' episode "Living With Earth: Preserving the Legacy" on YouTube
Television series by the Annenberg Foundation PBS original programming Science education television series 1992 American television series debuts 1992 American television series endings 1990s American documentary television series