Environmental Geology--not a discipline, but a collection of important topics

Earth Materials--rocks, minerals, soils, energy resources, water
      Concerns: extraction, resource limitations, environmental impacts

Natural Hazards--floods, landslides, earthquakes, tsunamis, volcanic eruptions
      Concerns: minimizing loss to life and property

Climatic Changes--global warming, ozone depletion, acid rain, deforestation
      Concerns: avoiding devastating changes such as desertification and sea level rise

Geologic Processes--how natural earth cycles produce both resources and hazards

Hydrologic Processes--interaction of oceans, surface and ground water

Land Use Planning--balancing the diverse demands for land with minimum conflict
      Preventing people from building in hazardous locations
      Preventing the pollution of critical groundwater resources
      Preventing long-term scaring and erosion of the landscape through reclamation
      Disposal of waste, some of which is highly toxic

The Uniqueness of the Earth -- Planetary Comparison
The earth has liquid water (hydrologic system) and a slightly mobile crust (tectonic system)
Most other planets have water in either the solid or gaseous state
Most other planets have either a violent or an inactive crust

The Earth is a small when looked at in Vertical Profile
The crust is only 5-70 km thick (the distance to Burbank or Sioux City)
The deepest mine in the world (Johannesburg, South Africa) is 4.8 km deep
The oceans average only 4 km in depth (the length of Vermillion east to west)
Half of the air in the atmosphere is below 5.5 Km above sea level, 99% below 32 km
Satellites orbit as low as 100 km above the earth (the distance to Sioux Falls)

The Environmental Crisis
Deforestation and resulting erosion and loss of usable land for humans and wildlife
Land and atmospheric impacts of mining and the eventual depletion of these resources
Loss or pollution of water resources (ground water, Aral Sea)
Population growth outpacing availability of food, water, and other earth resources
If we continue doing things as we are now, the next generation is going to have big problems.

Case Histories

Ducktown, Tennessee--Mining and deforestation for smelting in the mid 1800's caused a huge erosional scar on the earth that is only slowly recovering.  This could have been prevented through slower extraction, avoidance of forest clear-cutting, and proper land reclamation.

Aral Sea, Uzbekistan--over-use of water for agriculture in a marginal environment has destroyed both agriculture and fishing industries and generated the health hazard of salt flats.  Regulation of water use could have prevented all of these problems and created a sustainable system.

Antarctica Ozone Hole--the introduction of CFC refrigerants and nitrogen oxides into the atmosphere began breaking down the earth's protective Ozone Layer and created a "hole" over Antarctica that could have spread worldwide. The loss of protection from ultraviolet light would have greatly increased the incidence of sunburn and skin cancer.  Laws banning the release of CFCs have begun to repair the problem, though the long-term outcome is not yet known.

Sustainability
Using resources in a way that can continue indefinitely
Recycling metals, glass, and plastics to reduce the rate of extraction
Reclaiming land damaged by mining (restoring landscapes, planting trees)
Converting to renewable energy resources (solar, wind, hydroelectric, geothermal, etc.)
Regulating surface and ground water to prevent pollution and depletion
Preventing major climatic changes by avoiding emissions of CO₂, CFCs, etc.

General lack of awareness of geologic hazards, environmental impacts
New houses should be built in places that are safe to live (free of geologic hazards).
      Insurance programs often encourage risky investments rather than discouraging them.
If cars and gasoline are for sale, there should be no problems associated with using them.
We expect public officials to prevent long-term problems, but we typically elect them to meet our short-term interests.
How do we balance our immediate needs with consideration for future generations?

The Population Bomb
This is an emotional issue for many people because of religious beliefs.
It is largely solved in the industrialized world, but a major threat to Third World countries.
Exponential growth rates rapidly outpace resource availability.
Usually systems follow a bell curve over time (deer population, oil use, etc.).

Geologic Time
The earth formed, life evolved, and resources accumulated over billions of years.
What are the impacts of drastically changing the earth over a few hundred or thousand years?
Natural geologic cycles occur over long time periods; humans make large, short-term impacts.

Atomic structure: Protons and Neutrons in nucleus, Electrons in orbiting shells
Periodic Table of the Elements: lists elements in columns with similar bonding properties
Bonding: Ionic (transfer of electrons) & Covalent (sharing of electrons) to form compounds
      Anion: a negatively charged atom/ion (i.e. Cl^-, O^2-)
      Cation: a positively charged atom/ion (i.e. Na⁺, Ca²⁺)
Molecule: a set of bonded atoms making a discrete unit (i.e. H₂O, CO₂, C₈H₁₈)
Mineral: naturally occurring solid, orderly atomic arrangement and chemical composition
Mineral properties: hardness, density, crystal form, cleavage, luster, taste, HCl reactivity
Polymorphs: two minerals with the same composition but different structures (graphite/diamond)

Mineral Families
Silicates
      Framework silicates: quartz (pure SiO₂), feldspars (orthoclase, plagioclase)
      Sheet silicates: mica (biotite, muscovite), chlorite, clay minerals (kaolinite, talc)
      Double chain silicates: amphiboles (hornblende, serpentine [including asbestos])
      Single chain silicates: pyroxenes (augite, diopside, spodumene, jadeite)
      Orthosilicates (isolated tetrahedra): olivine, garnet
Carbonates: calcite (CaCO₃), dolomite
Phosphates: apatite, turquoise
Sulfates: gypsum (CaSO₄-2H₂O), barite
Sulfides: pyrite (FeS), chalcopyrite, sphalerite, galena
Chlorites: halite (NaCl), fluorite
Oxides: hematite (Fe₂O₃), limonite, magnetite, corundum, ice
Native elements: copper, gold, sulfur, graphite, diamond

Igneous Rocks (form from a liquid melt)
Composition
      Felsic: Granite/Rhyolite (continental crust material)
      Intermediate: Diorite/Andesite
      Mafic: Gabbro/Basalt (oceanic crust material)
      Ultramafic: Peridotite/Komatiite (mantle material)
Texture
      Phaneritic (coarse-grained, intrusive): Granite, Diorite, Gabbro, Peridotite
      Aphanitic (fine-grained, extrusive): Rhyolite, Andesite, Basalt, Komatiite
Volcanic glass: Obsidian, Pumice

Metamorphic Rocks (recrystallized in the solid state)
Factors: temperature, pressure, intergrannular fluids
Low vs. high grade metamorphism--indicated by index minerals, partial melting
Foliation--planar texture in rock running perpendicular to stress
Settings: burial metamorphism, regional metamorphism, contact metamorphism

Sandstone  >>>  Quartzite
Limestone  >>>  Marble
Shale  >>>  Slate  >>>  Phyllite  >>>  Schist  >>>  Gneiss
Granite  >>>  Gneiss
Basalt  >>>  Greenschist  >>>  Amphibolite  >>>  Granulite

Sedimentary Rocks (formed at earth's surface from sedimentary particles)
Usually form as horizontal layers of sediment in a body of water and later solidify
Superposition: the law that overlying layers are younger than underlying layers

Clastic sediments--made from fragments of preexisting rocks (via weathering & erosion)
     Conglomerate/Breccia, Sandstone, Siltstone, Shale, Coal
Chemical sediments--sediments precipitated out of water (organic or inorganic)
    Limestone (Chalk, Coquina, Oolitic ls.), Dolostone, Rock salt, Rock gypsum
Sorting--the process by which similar clastic particles are collected together
Sedimentary structures--cross bedding, mud cracks, varves
Lithification--occurs by the compaction and/or cementation of sediments

The Rock Cycle
Rocks can be converted from one type to another through heating, melting, and weathering.
This "recycling" of rocks is how the earth is reshaped by the Tectonic and Hydrologic Systems.

Strength of Rocks
Some rocks are very solid while others (e.g. clays) are very weak and tend to creep
Rock strength can be greatly reduced by fractures, sedimentary layers, and foliation
At depth, rocks under high temperature and pressure can gradually flow into folds
Rock strength and orientation of layers/foliation must be considered in construction
      Slope cuts for roads and buildings have led to landslides
      Dams have ruptured due to weakness in surrounding bedrock, causing flooding
      Earthquakes result from large-scale shifts in rocks and can cause clays to liquify

Tectonic System--driven by internal heat, internal activity of the earth, builds mountains
      Resources: rocks, minerals, ores, geothermal/nuclear energy
      Dangers: earthquakes, volcanic eruptions, tsunamis, landslides
Hydrologic System--driven by heat from sun, atmospheric circulation, erodes mountains
      Resources: water, salts, hydroelectric/wind/solar energy
      Dangers: Hurricanes, tornados, floods, landslides

The earth is a machine running at an appropriate speed--good balance of resources & dangers

Earth's Interior
Solid inner Core & liquid outer Core: metallic nickel and iron, gives earth a magnetic field
Solid but plastic Mantle: iron rich silicate minerals, asthenosphere flows over time
Thin rigid Crust: iron poor silicate minerals, "floats" on mantle, "sinks" at subduction zones

Evidences for internal structure: earthquake waves, earth density, magnetic field, meteorites
Reason for internal structure: gravitational differentiation by density (heavy stuff sinks)

Types of Earth's Crust
Oceanic Crust--basaltic, dark, density 3.0 g/cc, 1200ºC melting temp., 4000 m below sea level
Continental Crust--granitic, light, density 2.8 g/cc, 700ºC melting temp, most above sea level

Plate Tectonics--Earth's crust (lithosphere) is composed of rigid plates that move as units
Most activity (earthquakes, volcanoes, etc.) occurs at plate boundaries

Types of Plate Boundaries
1) Divergent--plates move apart, new magma rises to fill the gap forming basalt
      Physiographic features: mid oceanic ridges (in ocean), rift valleys (on land)
2) Transform--plates slide past each other, no creation or destruction of crust
      Physiographic features: transform faults (in ocean), strike slip faults (on land)
3) Convergent--plates collide and are destroyed or fused together
      a) oceanic/oceanic collisions--two pieces of oceanic crust collide and one is subducted
            Physiographic features: deep trenches and parallel island arcs in ocean
      b) oceanic/continental collisions--oceanic crust is subducted under continental crust
            Physiographic features: deep trenches paralleling continents, volcanic mountain range
      c) continental/continental collisions--two continents collide and fuse, forming high mountains
            Physiographic features: very high mountains in the middle of continents (Himalayas)

Ocean basins open & close on ~200 million year cycle, oceanic crust is subducted & destroyed
Continents are permanent (up to 4 billion years old) but break up & collide as they raft about

Origin of Crustal Rocks by Partial Melting
Peridotite      >>      Basalt                  >>      Andesite      >>      Granite

(Mantle)            (Oceanic crust)            (Composite             (Continental crust)
                       (Shield volcanoes)           volcanoes)                     (Plutons)

Highest melting temp.  <----------------------------------------------------->      Lowest melting temp.
Lowest viscosity  <------------------------------------------------------------>   Highest viscosity

Driving Forces of Plate Tectonics
Convection currents in the earth's mantle may carry the plates along like scum on moving water.
Ridge push" may result from the high elevation of the mid-oceanic ridges.
"Slab pull" may result from subducting slabs, which are cold & dense and want to sink.

Oceanic Crust
New oceanic crust is being created at mid-oceanic ridges (spreading centers).
      Oceanic crust is youngest near the ridges and becomes progressively older with distance.
      Oceanic crust is magnetically striped from reversals in the earth's magnetic field.
Old oceanic crust is being destroyed (recycled) in subduction zones (deep-sea trenches).

Continental Crust
New continental crust is being created as magma from subduction zones rises to the surface.
The total amount of continental crust has been constantly increasing throughout earth history.
Continents can grow through inflation and collision or be split by rifting, but never subduct.

Continental margins along plate boundaries are called "active margins" or "leading edges."
      Tectonic hazards are high (i.e. west coast of the United States).
Continental margins in the middle of plates are called "passive margins" or "trailing edges."
      Tectonic hazards are low (i.e. east and south coasts of the United States).

Hot Spots
Hot Spots in the mantle create island chains as a plates moves across them (Hawaiian Islands).
In some cases hot spots lead to plate rifting, usually forming a triple junction (East Africa).

Island Chains
1) Island Arcs--granitic rock, parallel subduction zones, all islands the same age (Aleutians).
2) Hot Spot Chains--basaltic rock, age of islands sequential down the chain (Hawaiian Islands).

Isostasy
The elevation of a floating object adjusts as mass is added or removed.
Mountains, like icebergs, have deep roots; erosion, like melting, causes the mass to rise.
Continental crust, being denser than oceanic crust, rides at a higher elevation.
After millions of years of erosion, a mountain's ancient roots are exposed at the surface.
Isostatic adjustment can sometimes lead to severe earthquakes even in plate interiors.

Implications for Environmental Geology
Plate tectonics is what gives the earth its unique appearance and features (oceans, mountains).
Earthquake, volcano, and tsunami hazards are strongly correlated with plate boundaries.
Many earth resources are created in certain tectonic settings (minerals, fossil fuels, evaporites).
Moving continents explains many out-of-place features (glaciated rocks at equator, arctic coal).

Earthquakes occur from the release of elastic stress along faults
Fault types: normal faults, reverse faults, strike-slip faults

Focus: the point of earthquake rupture
Epicenter: the point on the earth's center directly above the focus

Types of Earthquake Waves (in order of speed from fastest to slowest)
P-waves (compression waves): particles oscillate parallel to wave motion
S-waves (shear waves): particles oscillate perpendicular to wave motion
Surface waves: travel on surfaces, particles oscillate in circles

Wave frequency: the number of waves passing a point per second
Wave period: the number of seconds between the passing of wave peaks
      Lower frequency waves (longer period waves) tend to do more the most damage.

Earthquake Magnitude
Richter magnitude (M): largest magnitude 100 km from epicenter measured in logarithm of displacement in microns (millionths of a meter) on a standard seismograph.
Moment magnitude (M_W): similar to Richter scale but takes rock characters into consideration.
Modified Mercalli Scale: twelve divisions based on effects (perceptions and damage).
Ground acceleration: g forces exerted on the ground during an earthquake (1 g is the acceleration of gravity at the earth's surface, 9.81 m/sec²).

The Earthquake Cycle
Tectonic plate movement is gradual and constant, but faults can lock and refuse to move.
      Elastic strain builds up until it exceeds the strength of the rock, causing elastic rebound.
      Earthquake intensity is usually greatest in the direction of the suddenly moving rock.
Frequent small earthquakes indicate that a fault is moving smoothly.
Lack of any earthquakes in a region suggests that elastic strain is building on a locked fault.
Foreshocks and aftershocks of lesser magnitude are common around a major earthquake event.
Seismic gap: a section of fault that has been earthquake free fr a long time and is expected to have a large magnitude earthquake

Human caused earthquakes: reservoir filling, deep waste disposal, nuclear explosions

Earthquake Effects
Ground Shaking: controlled by earthquake intensity and local rock type, causes the most damage
Ground Rupture: the shifting of ground along a fault can create a new topography.
Liquefaction: shaking turns unconsolidated saturated ground to fluid, buildings can fall or sink
Landslides: landslides caused by ground shaking can also do extensive damage
Fires: electric and fuel pipeline failures commonly lead to fires in populated areas.
Tsunamis: seismic waves traveling 800 km/hr on the ocean can devastate coastal communities.

Seismic Prediction
Long term: study of tectonic plate & fault activity, finding seismic gaps
      Conditional probabilities: estimate of frequency of given magnitude earthquakes
Short term: searching for earthquake precursors, such as foreshocks, ground tilt, well level changes, radon gas, animal activity

Adjustments to Earthquake Risk
Structural protection: build buildings, roads, and dams according to code specifications
Land-use Planning: avoid building in the most earthquake prone areas
Insurance and Relief measures: communities must prepare for earthquake risk.
Warning systems: radio & loudspeaker system providing up to one minute of warning

Magma: molten rock with dissolved gasses and sometimes preformed crystals
Lava: magma that has emerged from a volcanic vent
Intrusion: a body of magma that cooled in the earth without reaching the surface
Extrusion: a body of lava that cooled on the earth's surface after eruption

1) Fluid Magma
Mafic or basaltic magma (50% silica content) tends to be much more fluid.
It reaches the surface easily even through small conduits to form broad Shield Volcanoes or even flat basaltic plateaus (i.e. Columbia River Plateau and Snake River Plain in NW USA, Deccan Traps in India).
It generally cools underground only in narrow sheets that either parallel layers of sedimentary rock (sills) or cut across preexisting structures (dikes).

2) Intermediate Magma
Intermediate or andesitic magma (60% silica content) often flows to the surface to form steep-walled and explosive Composite Volcanoes (Stratovolvanoes).

3) Viscous Magma
Felsic or granitic magma (70% silica content) tends to be viscous because the silicon and oxygen atoms hang tightly together even in the liquid state.
It has difficulty reaching the surface and commonly cools underground in gigantic bodies of Granite called batholiths (>100 km²) or stocks (<100 km²).
When granitic magma does reach the surface is forms small domes of Rhyolite.

1) Shield Volcanoes
The largest of volcanoes, have very gentle slopes, made mostly of basalt
Erupt fairly quietly and continuously by outflowing of fluid magma
Magma can flow many miles and "roof over" to form lava tube caves
Cinder cones (made of pyroclastic rocks) are often associated with them
Examples: Hawaiian Islands, Iceland, nearly all oceanic volcanoes

2) Composite Volcanoes (Stratovolcanoes)
Smaller volcanoes with steep walls and high peaks, made mostly of andesite
Erupt violently and dangerously, throwing huge clouds of volcanic ash into the air
Eruptions often cause dangerous pyroclastic flows and mudflows
Examples: Mount St. Helens, Mt. Rainier, Mt. Vesuvius, Mt. Pinatubo, Mt. Fugiyama

3) Volcanic Domes
Expanding domes made mostly of rhyolite (the aphanitic form of granite)
Can be very explosive and dangerous because of the very high silica content
Example: Mt. Lassen

Other Volcanic Features

Hot springs and Geysers--groundwater heated by contact with hot volcanic rock

Craters--circular depressions up to 5 km in diameter commonly found at the tops of volcanoes formed by explosions or collapse due to magma retreat

Calderas--gigantic depressions that may contain vents and other features within them; some are associated with the most extensive pyroclastic eruptions (Yellowstone, Long Valley)

Vents--openings through which magma extrudes in any location

Volcanic Hazards

Lava flows--liquid lava flowing downhill from a volcanic vent
      Attempts have been made to control flows with barricades, canals, and water cooling.

Pyroclastic flows--airborne flows of hot ash and gasses moving up to 100 MPH (nuée ardentes)
      These are extremely dangerous because they can occur without warning and fry everything in their path, even though little material is deposited.

Ash fall--Raining down of fine ash following a viscous volcanic eruption
      These cause no extreme dangers but lead to respiratory problems and burial of the ground.

Toxic gas--rarely carbon dioxide can be released, replacing air in a local area
      Near Cameroon, West Africa, 1700 people died in 1986 from such an "eruption."

Lahars--volcanic eruptions often melt snow and combine to form huge mud flows
      These often flow down valleys as great floods and inundate populated areas.

Drainage basin (watershed)--the land area drained by a particular stream or river
Floodplain--the area covered by a river during flood stage, through which the river meanders
Stream gradient (slope)--vertical drop per length of river (decreases downstream)
Base level--the lowest level that a river can achieve, set by sea or lake level

Discharge (flow rate)--the volume of water in a river passing a given point per second
Capacity--the volume of sediment in a river passing a given point per second
Competency--the largest size of sedimentary particle that a particular river can carry
Bed load--larger sedimentary particles (pebbles, sand) that move by skipping or rolling
Suspended load--finer sediments (silt, clay) suspended in the river water (making ir brown)
Dissolved load--dissolved substances (mainly ions like Ca⁺ and HCO₃^-) in the river water

Meandering river--winding river passing through a floodplain with a single channel
  Meanders form and migrate by cutbank erosion and point bar deposition
  Meander cutoff produces oxbow lakes
  The meandering river gradually wanders around the floodplain
Braided stream--stream overloaded with sediment, many channels splitting and rejoining
Delta--depositional structure where a river dumps its load into a body of water
Alluvial fan--depositional structure where a river dumps its load on land (mountain front)

Dam construction causes filling of the reservoir by sediment plus erosion downstream
Thus lakes are temporary and unnatural features that are quickly filled in and destroyed
Introduction of excess sediment partially dams a river, disturbing its profile and making rapids

Flooding--a river or other body of water overflowing its normal channel or limit
  Upstream floods--local floods caused by local heavy rains (flash floods)
  Downstream floods--long floodplain floods caused by high regional runoff in the drainage basin
Excess water can evaporate (helped by pooling), infiltrate the ground (helped by lack of impervious cover), or enter the drainage system as runoff.  Urbanization increases impervious cover, thus decreasing infiltration and decreasing lag time (flashy discharge).

Stream Hydrograph--plot of stream discharge over time, showing peak and duration of flood
Flood-frequency Curve--shows probability of floods of various magnitudes for a given year
Recurrence Interval--the average interval between equal or greater magnitude floods

Prevention measures: floodplain regulation & zoning, levees, channelization, channel restoration

Coastal Hazards
Tropical Cyclones (hurricanes or typhoons)--low pressure centers, great wind speed, storm surge
Tsunamis (seismic sea waves)--generated by earthquakes, travel 700 km/hour,mostly in Pacific
Coastal Erosion--ongoing processes along shorelines caused by normal wave energy

Waves
Wave height--vertical distance between wave crest and wave trough
Wave length--distance between adjacent wave peaks or troughs
Wave period--the time for successive waves to pass a reference point

Storms--generate waves at sea according to wind speed, fetch (storm length), and duration
Swell--waves traveling freely across the ocean as a speed corresponding to their wavelength
Surf--waves reaching shallow water, slowing, breaking, and dissipating their energy

Coastal Processes
Wave energy cuts a notch, forming a wave-cut platform (beach area) and a receding sea cliff
      Sea cliff recession slows as the platform becomes too wide for many waves to cross.
Wave refraction (bending) causes wave convergence on headlands, wave divergence in bays
      Over time this causes coastlines to become straight or gentle curved.
Longshore drift (littoral transport) moves sand along the beach as waves hit the beach at an angle
      Over time spits, bars, and barrier islands dam off lagoons & thereby straighten the coast.
Tides cause sea level to change slightly and flood water in and out of coastal bays
      High tidal ranges make it difficult for typical wave-cut platforms & beaches to develop.

Causes of Coastal Erosion
Cutoff of incoming sand by the damming or diversion of rivers
Blockage of longshore drift by man-made coastal structures (see below)
      These can be compensated for through beach nourishment (trucking in of sand)
Sea cliff erosion by wave undercutting, wind, and normal rock weathering
      E-zones represent the areas expected to be eroded in a given number of years (E-10 line)

Coastal Modification Structures
Seawalls--built along beach or sea cliff parallel to shore to slow coastal erosion
      Wave reflection increases erosion seaward of the wall, often destroying beaches
Groins--linear structures extending out from beach perpendicular to shore
      Sand accumulates updrift of groin and erodes downdrift of groin
Breakwaters--built offshore but parallel to shore to create protection from waves
      Longshore drift is inhibited behind the breakwater, causing the filling of the bay
Jetties--pairs of structures around river or bay mouths running perpendicular to shore
      These protect harbors from waves but interfere with longshore transport

Coastal Populations
Most major cities have been built along coasts because of access to ship transportation.
Coastal property is considered valuable because of scenery and recreation.
Hurricanes and rising sea level are major threats to coastal populations.
Sea level may gradually rise as global warming melts the Antarctic and Greenland ice caps.

Estuaries (drowned river valleys)
Formed by rising sea level filling a stream valley with seawater
Examples: Chesapeake Bay, San Francisco Bay, Puget Sound, Long Island Sound
These protected waters have a high plant biomass (spartina grass, mangrove trees)
Estuaries provide quiet water areas for spawning by marine organisms.
Pollution and land reclamation have destroyed valuable fisheries.

Barrier Island/Lagoons
Form when longshore drift creates sand (beach) islands that cut off bays/lagoons
Examples: Assateague Island, Outer Banks of North Carolina, Padre Island/Laguna Madre
Channels between islands allow for tidal currents and have deltas on each side.
The islands are mobile geologic systems, but people still build homes on them.
Filling of lagoons for valuable real estate destroys important fish nurseries.

Coral Reefs
Require warm, clear, shallow water and a hard coastal substrate to develop
Examples: The Florida Keys are reefal islands; Hawaii & other islands are surrounded by reefs.
Corals secrete calcareous skeletons and can build upon their ancestors to stay at sea level.
As islands sink, reefs grow and evolve from Fringing Reefs to Barrier Reefs to Atolls.
Barrier reefs and atolls present hazards to shipping because they are shallow but hard to see.
Pollution, siltation, and physical damage can destroy coral reefs.

Mass Wasting--the down-slope movement of rock/soil by the force of gravity
It is concentrated on slopes and provides material for streams to wash away.
It tends to increase with steeper slopes, with higher water saturation, and with loss of vegetation.

Types of Mass Wasting

Creep--the gradual downhill movement of soil with highest velocity at the surface

Rockslides & rockfalls--sudden movement of rocks or rock masses on steep slopes
      Rockslides occur most often when bedding planes of rock layers point downhill
      Rockfalls produce large talus cones on mountains with much freezing/thawing

Slumps and earthflows--flow or rotation of semi-solid masses of earth

Mudflows--fluid masses of soil that move down steep drainage systems
      Lahars--mudflows caused by volcanic eruptions

Subsidence--the lowering of the ground due to water extraction, mine collapse, etc.

Sinkholes--local collapse features of underground caves, mines, salt domes, etc.

Quick clays, quicksand, permafrost--special kinds of mass movement

Human activities that promote mass wasting
Steepening of slopes in road cuts, terrace edges, etc.
Building of terraces on slopes, thus increasing infiltration and ground saturation
Building of dams and canals, thus greatly increasing local ground saturation
Construction of buildings on slopes, thus adding weight to the ground

Human strategies for preventing mass wasting
Drainage control to carry water away rather than letting it infiltrate the ground
Grading of a slope to decrease the upper unconsolidated mass, or drained terracing
Slope supports--retaining walls and other supports, best if tied to bedrock

Potentially rapid mass movement needs to be monitored as with volcanoes & earthquakes.
South Dakota landslides: Pierre Shale near Missouri River

Portuguese Bend landslide, near Los Angeles, California (1956-1984)
Movement varied from 0.3 to 2.5 cm/day increasing during wet years
Homes moved up to 50 m, but many remained occupied & used jacks to level them
The slide was deactivated in 1985 by digging dewatering wells.

Thistle landslide, Spanish Fork Canyon, Utah (1983)
3-million-cubic-meter earth mass reactivated during wet (El Nino) year.
Over several days the landslide filled the valley and flooded the town of Thistle.
A tunnel was drilled through surrounding rock to drain the lake and prevent flooding.

Gros Ventre rockslide, Teton area, Wyoming (1925)
Tilted sandstone layer slid on underlying shale when undercut by river.
Sudden rockslide filled the valley, creating a lake.

Madison Canyon landslide, Yellowstone area, Montana (1959)
32,000,000 m³ of solid rock suddenly slid down into a canyon bottom.
It caused tremendous winds and killed over 20 people in a campground below.
It was triggered by 7.1 magnitude earthquake 30 km east of the site.
It dammed up the Madison River, creating Earthquake Lake.

Vaiont Dam, Italy (1963)
Filling of the Vaiont Reservoir weakened the steeply-dipping bedrock.
240,000,000 m³ of rock slid down instantly and filled the reservoir.
The slide threw out water on several towns and killed 2600 people.
The reservoir and heavy rains had increased groundwater saturation.
Precursor movement increased from 1 to 100 cm/day.

Giant prehistoric mass movements
Rockslide in Iran: 12 km; Blackhawk Slide, California: 8 km
Giant slide flow great distances on a cushion of air.

Snow avalanches: a serious hazard to mountain valley towns, resorts, and highways.

Subsidence
Sinkholes form from cave-ins in soluble rock such as limestone and salt domes or in mines.

Glaciers: thick masses of ice that flow under their own weight
1) Alpine Glaciers (Valley Glaciers)--flow down mountain valleys
2) Continental Glaciers (Ice Sheets)--flow outward from a center

Glacier formation requires that precipitation outpaces melting so that ice accumulates over years.
Glaciers move by internal flow and basal sliding.  The upper center portion moves most quickly.
During unusual events called surges, glaciers can move up to 54 M (180 ft.) per day.

Parts of Glaciers
Zone of Accumulation--zone where snow accumulates and recrystallizes to form ice
Equilibrium Line--point of maximum glacial flow (near snowline)
Zone of Ablation--zone where ice melts and releases its water and sediment load
      Alternately glaciers can flow into the sea or a lake and form icebergs by calving.

Features left by Glaciation
Erosional: striations, cirques, horns, arˆtes, glacial troughs (U-shaped valleys), truncated spurs, hanging valleys, tarns, paternoster lakes, Roche Moutonnées, fjords

Depositional: till, moraines (lateral, medial, terminal, recessional, ground), drumlins, kames, eskers, kettle lakes, outwash plains, erratics, varves

Icebergs--floating freshwater ice blocks calved from glaciers
Ice-marginal lakes--large lakes from ice dams or ice-weight depressions (Great Lakes)
Pluvial Lakes--large lakes that form in cool glacial times due to low evaporation (L. Bonneville)
Ice Ages--periods of great expansion of polar glaciers and pluvial lakes
      The Pleistocene Epoch is the most recent example of a major ice age.
      Ice ages are controlled by continental positions and orbital variations.

Deserts
Falling air masses compress and warm, preventing precipitation.
Deserts for where descending air is the usual situation.

Low-latitude Deserts--caused by prevailing winds (20-30ºN/S)
Rain Shadow Deserts--where air descends over mountains
Mid-latitude Deserts--on large continental interiors

Definitions of Deserts
Less than 25 cm (10 inches) of rain per year, evaporation outpaces precipitation
Vegetation sparse, soils thin to non-existent, rapid stream runoff

Effects of Wind and its Landforms
Deflation (sand removal by wind) creates blowouts, desert pavement, and ventifacts.

Sand moves by saltation, creating migrating sand dunes where sand is deposited.
Sand is driven up the shallow face of a dune then falls down the steep slip face.

Fine particles are transported in suspension by the wind and deposited as loess.
Glaciers grind up rock that is blown out of glacial streams to form loess beds downwind.

Desertification--conversion of marginal (semiarid) lands to deserts through bad agricultural practices and erosion of soil.

Oxygen isotopes give the best indication of past temperatures at various latitudes.
Isotope fractionation is most pronounced at low temperatures.

Greenhouse Effect and Global Warming
Solar energy arrives as visible light, which passes easily through the atmosphere.
This energy leaves the earth as infrared light, which is absorbed are reradiated by certain gases.
Increases in H₂O vapor, CO₂, CH₄, N₂O, CFC's, etc. increase the greenhouse effect.

Glacial ice currently occupies over 2% of the earth's water reservoir.
If all glaciers melted, sea level would rise 60-70 M (200-230 ft.) above its current level.
During the peak of the last Ice Age sea level was 150 M (500 ft.) lower than at present.

El Nino is a phenomenon where normal coastal upwelling in Peru ceases for unknown reasons.
Global climate patterns change as a result, causing famines in some places and floods in others.
This demonstrates how little we know about the long-term effects of changing the atmosphere.

Surface water--rapid return to ocean but little volume at a given time, follows drainage basin
      Instream uses--water use without removal (navigation, hydroelectric, cooling, recreation)
      Offstream uses--removal of water from the stream (irrigation, public and industrial water)
      Consumptive use--offstream water that never returns to a stream or ground water supply
      Discharge patterns--discharge over time, ideal differs for different stream uses
            Wildlife needs large seasonal fluctuations to restore various habitats
            Hydroelectric power needs large day-night fluctuations to meet electrical demands
            Navigation prefers an unchanging discharge pattern to preserve shipping channels
      Water importation--canals and aqueducts transport water from source areas to need areas
            Southern California and New York City import surface water from outlying areas

Ground water--very slow travel but very large "stored" volume, flows according to Darcy's Law
      Porosity--fraction of pore space in a rock that can hold intergrannular fluids
      Permeability--ability of rock to transmit fluids
      Water table--the upper surface of the saturated zone, the underground "water surface"
      Zone of Aeration (Vadose zone)--above the water table, pore spaces are filled with air
      Zone of saturation (Phreatic zone)--below the water table, pore spaces are full of water
      Aquifer--a useful reservoir of ground water, usually formed in a gravel or sand layer
      Aquiclude or Aquitard--rock material impermeable to ground water, such as shale
      Recharge--any process that adds water to an aquifer (infiltration, canal or pipe leakage)
      Discharge--any process that removes water from an aquifer (spring, well)
      Cone of depression--shape of water table drop around a pumping well
      Karst--areas of sinkholes, dissolved underground caverns, and springs in limestone

Ground Water Problems
Hard water--high concentrations of dissolved calcium and magnesium from rock dissolution
      Water softeners exchange these ions for sodium which doesn't deposit on dishes/bathtubs

Ground water overdraft--removal of ground water at a rate that greatly exceeds aquifer recharge
      This is a serious problem in the High Plains Aquifer of South Dakota to Texas

Salt-water intrusion--pulling sea water into a coastal fresh water aquifer by over-pumping wells
      This is a problem on Long Island, New York, and around Miami, Florida

Compaction and Subsidence--Heavy removal of ground water causes compaction and reduced porosity and permeability of rocks.  This is a problem in central California and Italy.

Definitions of soils
1) Solid earth altered by physical, chemical, and biologic processes to support plant life
2) Solid earth material that can be removed without blasting (regolith, engineer's definition)

Soil-forming processes
Key factors: parent material, temperature, rainfall, organisms, slope, and time
Weathering--physical and chemical breakdown of bedrock into tiny fragments
Erosion and deposition--movement of weathered bedrock from one place to another
      Residual soil--made of unmoved weathered bedrock
      Transported soil--made of transported weathered material (floodplain soils, etc.)
Organic processes--deposition of plant litter, rooting and burrowing, etc.
Leaching (eluviation)--removal of soil components by descending ground water
Accumulation (illuviation)--deposition of dissolved ground water components

Soil horizons (began as A-B-C with additional layers defined later)
O horizon--surface layer of pure organic matter (present mainly in forest soils)
A horizon--mixture of organic matter and highly altered mineral material, dark color
E horizon--zone leached of iron-bearing components, little organic matter, light color
B horizon--weathered bedrock enriched with clay, iron oxides, silica, and carbonates by accumulation via descending ground water from the layers above it (often red in color)
K horizon--a layer with accumulated carbonate filling all pore spaces between grains
C horizon--partly altered bedrock still containing many bedrock blocks
R horizon--solid unweathered bedrock below the soil

Soil properties
Color--reflects composition (brown or black from organics, red or yellow from iron oxide)
Texture--particle size (sand 2-0.05 mm, silt 0.05-0.002 mm, clay < 0.002 mm)
      Loam--a soil with similar amounts of sand, silt, and clay
Structure--ability of soil to form lumps or clods (peds) which resist erosion

Soil nutrients
Nutrients are the materials needed for plants to grow (nitrogen, phosphorus, potassium, etc.)
Various nutrients can come from altered bedrock or plant litter broken down by bacteria
Leaching tends to oxidize and remove nutrients from soils, leaving them infertile
Soil nutrients can be artificially added to increase soil productivity (fertilizers)

Soil taxonomy (partial list)
Pedalfers--fertile leached acidic soils rich in iron and aluminum (Eastern U.S. & Canada)
Pedocals--thin unleached alkali soils formed in dry climates (Southwestern U.S.)
Laterites--thick nutrient-poor extremely leached soils of iron and aluminum (tropical rain forests)

1. Entisols--soils without layering, except perhaps a plowed layer
2. Vertisols--soils with upper layers mixed due to expandable clays
3. Inceptisols--young soils with no horizon development (often formed on recent alluvium)
4. Aridisols--thin desert soils often containing caliche (carbonate) from prior accumulation
5. Mollisols--calcium and organic-rich prairie soils with considerable leaching and accumulation
6. Spodosols--sandy, acidic, humic soils formed in humid forests with sandy bedrock
7. Alfisols--other acidic soils with clay-enriched subsoils
8. Ultisols--similar to alfisols but with weathering more advanced (includes some laterites)
9. Oxisols--deep leached tropical soils containing iron and aluminum oxides and clay (laterites)
10. Histosols--Very organic soils (peat, muck, bogs)

Soil erosion
Soil formation is part of the natural weathering/erosion process that gradually levels the land
Soil erosion rate depends on many factors: slope, rainfall, vegetation cover, soil cohesion, etc.

Human modification of soil tends to destabilize it, leading to greater rates of erosion
Soil erosion tends to degrade soils by removing the rich (most weathered/organic) upper layers
Sediment pollution is the filling of canals, reservoirs, cities, etc. with unwanted sediment

Urbanization factors
During construction phase erosion can be extreme due to presence of unprotected soils
After development erosion is low, but high urban runoff can erode nearby drainage areas

Off-road vehicles often cut channels on steep hillsides that become natural erosion channels
In windy areas, such as barrier islands, even walking trails can lead to serious soil erosion

Soil pollution
Soils can become polluted with organic chemicals (oils, pesticides), heavy metals, etc.
These can constitute soil and/or ground water issues depending on the water table & water flow
Bioremediation is the use of microbes to clean a soil, often enhanced by pumping of gases

Land-use planning and soils
Problems
Agricultural land usually has a lower value than urbanized land, making it hard to preserve.
Developers generally have a short-term, profit-oriented perspective on land use.

Solutions
Zoning practices and tax incentives can deliberately preserve prime agricultural land.
Soil surveys allow land-use planners to develop well-balanced land-use strategies.

Some uses of Earth Resources
Building/road materials: quarried rock, gravel, sand, limestone, gypsum
Metals: gold, silver, platinum, copper, iron, aluminum, lead, zinc, etc.
Abrasives: diamonds, corundum, diatomite
Ceramics: clay minerals
Gemstones: diamond, corundum, beryl, garnet, topaz, zircon, etc.
Fuel: coal, petroleum, natural gas, uranium (covered in Chapter 13)

Resource--concentration of natural material that can be extracted for a profit
Reserve--the portion of a resource now available for legal extraction at a profit
Ore--the raw material from which a resource (usually a metal) can be mined at a profit
Concentration factor--ratio between concentration in an ore deposit and average concentration

Responses to Limited availability
Find more of the resource to extract (deeper mines, sea floor, asteroids, etc.)
Find a substitute material to suite the same purpose
Recycle what has already been extracted and thrown away
Use less and make more efficient use of what is already available
Do without

Geologic Concentration Processes
Igneous cooling--feldspar, quartz, lithium, gold, diamonds (from kimberlite), pegmatite minerals
Metamorphism--garnet, talc, marble, quartzite, graphite, asbestos
Hydrothermal precipitation--Copper, gold, silver, mercury, lead, zinc, galena, sphalerite
Placer (sedimentary) sorting--gold, silver, platinum, diamonds, sand, gravel
Biological activity--limestone (building stone, cement), calcium phosphate (fertilizer)
Ancient (Precambrian) anoxic environments--iron (from Banded Iron Formations)
Weathering (soil leaching)--aluminum (from bauxite), iron
Evaporation of water--salt, gypsum, borax, potash

Types of resources and mining practices
Metallic vs. Non-metallic resources
Underground mining vs. strip (open pit) mining of ore

Waste from mines
Overburden--non-economic material removed in order to get to resource
Tailings--solid wastes from mining

Reclamation--refilling of mine pits and restoration to a natural topography
Reclamation adds to the economic cost of mining, raising the resource price.
But it helps alleviate many of the long-term negative effects of mining.

Pollution from mining
Siltation of streams from uncontained mining and processing tailings
Heavy metals--cause disorders of central nervous system, bone loss (Itai-Itai disease)
      These often undergo selective concentration in the food chain.
Processing additives--such as cyanide for gold processing
Acid mine drainage from sulfide mining (kills plants, fish)

Biotechnology--use of bacteria to digest harmful compounds into harmless ones
Homestake Mine used biotechnology to remove cyanide from gold treatment waters.
Bioassisted leaching is used to concentrate gold in Nevada (an alternative to cyanide).
Engineered wetlands are used to neutralize acids and remove heavy metals from mine wastes.

Advantages of metal recycling
1) Less expensive than extracting more primary ore
2) Leaves larger reserves for future generations
3) Reduces amount of waste material placed in landfills

Examples of energy savings from metal recycling
Aluminum from bauxite      300 MJ/kg     Plus expensive international transportation
Recycled Aluminum           7 MJ/kg         Plus cheap local transportation
Contaminated scrap Al      30 MJ/kg

Steel from iron ore       28.5 MJ/kg
Steel from scrap          1.26 MJ/kg

Petroleum is made of hydrocarbons (C_xH_2x+2) created in the earth's crust from fossil debris.
Petroleum includes oil, such as octane (C₈H₁₈), and natural gas, which is mostly methane (CH₄).
Both form as kerogen (from unoxidized plant debris) is driven up through rock by heat/pressure.
Higher temperatures create higher proportions of the lighter oils and natural gas.
The heaviest components of petroleum are wax and heavy oils with long hydrocarbon chains.

Petroleum traps are required to catch the petroleum on its way up, otherwise it escapes.
Traps consist of a porous reservoir rock (like sandstone) and a cap rock (like shale).
Anticlines, salt domes, faults, unconformities, and limestone caverns often create reservoirs.
Locating petroleum traps for drilling is the major occupation of petroleum geologists.

500 billion barrels of oil have been consumed, and a trillion exist in known reserves.
Ever increasing petroleum consumption means the supply is severely limited.
Petroleum deposits are unevenly distributed on earth, with the Middle East having a huge share.
About 90% of U.S. petroleum reserves have already been consumed.
The U.S. currently imports over half its oil from other countries.
The U.S. also has limited natural gas reserves and is importing about 15%.
Oil spills from tankers and offshore rigs are a major environmental hazard of petroleum.

Finding more petroleum will become increasingly expensive as the big reservoirs are emptied.
Enhanced recover involves using hot water/steam, acids, and explosives to extract more oil.
Deeper "geopressurized zones" of natural gas may be found, but extraction will be expansive.
Methane hydrates exist sea-floor sediments, but there's no technology for extracting them.
Oil shales and tar sands represent land-based petroleum reserves that must be mined (like coal).

Coal is altered plant debris (usually from coastal swamps) that must be mined.
Peat > Lignite > subbituminous > bituminous > anthracite > metaanthracite > graphite
Strip mining involves removing overburden, whereas underground mining leaves coal behind.
Coal is mostly used for electric power plants (i.e. Sioux City) and steel plants.
Coal is plentiful and will last for hundreds of years at its current rate of consumption.
Coal is expensive to transport, produces ash, and must be scrubbed for sulfur (acid rain).
Deaths from coal mining outnumber all other energy-extraction-related deaths combined.

Fossil fuels are considered non-renewable because they're being used far faster than they form.
They add CO₂ and pollutants to the air, causing global warming and other problems.

Nuclear Fission (nonrenewable, 7% of world energy)
The nuclei of certain heavy atomic nuclei (²³⁵U, ²³⁹Pu) can split and release enormous energy.
Each fission releases neutrons that can induce other fissions, creating a chain nuclear reaction.
Mined uranium (the heaviest natural element) is 99.3% ²³⁸U and only 0.7% fissionable ²³⁵U.
Enriching the uranium to 5% ²³⁵U creates a useful fuel for most nuclear power plants.
A breeder reactor converts otherwise useless ²³⁸U into ²³⁹Pu, which can fuel other power plants.
This requires reprocessing of spent fuel to separate uranium, plutonium, and nuclear waste.
Jimmy Carter ended U.S. breeder research, but France depends heavily on breeder reactors.

The core of a nuclear power plant consists of fuel rods, control rods, and a moderator (water).
There are several levels of containment and many safeguards to prevent overheating of the core.
Fission boils water, and the steam drives a turbine which drives an electric generator.
The only deadly nuclear accident was in Chernobyl, Ukraine (then USSR) in 1986.
Permanent disposal of nuclear waste is still unresolved in the U.S. (see Chapter 15).

Nuclear Fusion (experimental)
The joining of hydrogen nuclei into helium also releases enormous amounts of energy.
Advantages include an unlimited fuel supply (hydrogen) and inert byproduct (helium).
Initiating and containing the high temperatures present severe technological problems.
Cold fusion (low temperature activation) has been hyped but has not proven to work.

Solar Energy (renewable, intermittent)
Includes passive and active space heating, thermal and photovoltaic electric generation.
Solar energy is intermittent and is mostly useful in desert areas such as the southwestern U.S.
Photovoltaic is most viable for small applications, in remote locations, and on satellites.

Geothermal Energy (mostly renewable)
Geothermal is useful in a few areas with a high geothermal gradient (shallow magma chambers).
The Geysers (north of San Francisco) takes advantage of pressurized underground steam.
Elsewhere water is cycled into the ground and heated (for electric generation or space heating).
Hot water dissolves minerals which can clog pipes and cause pollution if released.
South central South Dakota has geothermal potential, but few live there to take advantage of it.

Hydropower (renewable, 7% of world energy)
Hydropower is locally available along river courses where dam sites are feasible.
Electric output is dependent on head (water height) and water discharge (CFS).
This resource is already nearly maximally exploited and has environmental impacts.
Hydropower must compete with other river uses (navigation, irrigation, needs of wildlife).
Reservoirs can lead to a substantial evaporation loss, especially in deserts (southwest U.S.).
Tidal hydropower is locally available in coastal bays (France, Canada) but is intermittent.

Wind Energy (renewable, intermittent)
Wind provides economical energy in areas of frequent wind (midwest U.S., California, Hawaii).
Windmills, often in "wind farms," turn generators to add power to the electrical grid.
Land used for wind farms can still be used for agriculture, but windmills can be noisy.
This resource has become economical and is being exploited more each year.
Energy storage is a problem when wind energy is used without a backup resource.

Biomass Energy (renewable)
Crops, crop wastes, and trash can be burned for electricity or converted to alcohol fuel.
This can supplement agriculture, but also compete with it if used heavily.
Unlike fossil fuels, biomass adds no net CO₂ to the atmosphere because the carbon is cycled.
Burning of trash requires sorting so that no toxic materials are vaporized.
Ethanol gasoline contains 10% ethanol, which is a mixture that regular gasoline engines can use.

Ocean Thermal Energy Conversion (OTEC) (renewable)
The difference in temperature between surface and deep water in the tropic oceans is a resource.
Low-temperature coolants (ammonia, freon) can be boiled to generate low-efficiency electricity.
This has been tested in Hawaii, could also be used at sea to process aluminum ore.
Other forms of potentially harnessable ocean energy include waves and ocean current.

Solid Waste Disposal
By far the largest volumes of solid waste are derived from agriculture and mining.
These wastes sometimes contaminate surface and ground water, but they are usually left on site.

Municipal waste disposal takes up valuable space and can create a variety of health hazards.
Two valuable solutions are to recycle more materials and use some wastes as fuel.
      Paper makes up about half of solid waste and is useful for recycling and as a fuel.

A "sanitary landfill" is a site designed to hold solid waste without creating a public hazard.
A polluted liquid leaving a landfill via surface or ground water is called "leachate."
Leachate can be contained from downward infiltration by an impermeable liner (plastic, clay).
Un upper liner is also needed to prevent leachate overflow from rainwater ("bathtub effect").
Methane gas is produced in landfills by anaerobic bacteria and can be a hazard or resource.
      Methane can explode in high concentrations, plus it is a greenhouse gas.
      Some large landfills capture the methane and use it as a fuel or simply burn it.

Location considerations include topography, rock type, and ground water characters.
The Resource Conservation and Recovery Act of 1980 strictly regulates landfills.
      Landfills cannot be located in floodplains, wetlands, fault zones, or unstable areas.
      Landfills must have an impermeable liner and a leachate collection system.
      Operators must monitor surrounding ground water for specific toxic contaminants.
      Operators must have bonds to insure that monitoring continues for 30 years after closure.

Ocean dumping of trash and sewage was banned in 1988 in the United States.
Large volumes of dredge spoils are still dumped in the ocean.

Trash compacting, incineration, feeding to pigs, and composting are ways of reducing landfills.
Recycling is the best option for many wastes, and it saves natural resources and energy as well.
Paper, plastics, glass, and most metals can be recycled (often at a profit).
The biggest problem with recycling is the separation of different types of waste.

Liquid Waste Disposal
Sewage is the most abundant liquid waste.
It can be treated in individual septic systems on by municipal sewage treatment.
Septic systems involve a settling tank for breakdown of solids, and a leaching field for liquids.
Municipal treatment involves physical breakdown/separation & bacterial breakdown of organics.
Wastewater is then safe for release, and further purification can even make it drinkable.
Solids collected from municipal sewage plants can be used for fertilizer.

Toxic liquid wastes include acids, bases, organic solvents, oils, etc.
Some of these, such as used oil, are recyclable, but many are not.
The dilute-and-disperse strategy has been used in the past, but has caused serious health hazards.
The concentrate-and-contain strategy requires finding a secure site for storing liquid waste.
Landfills for liquid require extensive liners and leachate monitoring and collection systems.
Deep-well disposal can be accomplished in suitable geologic traps (similar to petroleum traps).
Some toxic wastes can be destroyed by bacteria or by burning, but others cannot.

Past unregulated or illegal dumping of toxic waste has created many environmental hazards.
The Superfund is generated from tax on toxic waste producers and has reached ~$12 Billion.
But ~$1 Trillion may be required to fully clean the over 40,000 identified toxic waste sites.

Nuclear Waste Disposal
Nuclear waste is generated at nuclear power plants and certain military facilities.
Gamma radiation is the most serious hazard, which can cause death or mutation (cancer risk).
These wastes will remain hazardous for many thousands of years.
Reprocessing of fuel rods and breeder reactors reduce waste volume, but not the total hazard.
As yet, no permanent repository for high-level nuclear wastes has been used in the U.S.

Proposals include seabed disposal, salt dome disposal, and deep crystalline rock disposal.
More ridiculous proposals include launching into space and glacier or subduction zone disposal.
Yucca Mountain, Nevada has been selected as the permanent repository for the United States.

Geochemical Cycles--the transfer of elements between different reservoirs such as the earth's crust, lakes and streams, the oceans, sediments, and the atmosphere.

Residence Time--the average length of time a substance remains in a particular reservoir.
      = Capacity (of a reservoir to hold that substance) / Rate of Influx (into that reservoir)

Pollutants have a residence time in the reservoir(s) where they are dumped, which becomes the half-life of the substance in the reservoir if the pollution ceases.

Point sources--discrete sources of pollution: gas tanks, septic tanks, industrial plants
Non-point sources--diffuse sources of pollution: agricultural areas, deforested areas, urban areas

Water Pollution Problems

Heavy metals--lead, mercury, zinc, cadmium, etc. concentrate in the central nervous system
      Sources: mine tailings, industrial wastes, lead pipes and paints

Other inorganic wastes--acids, bases, asbestos
      Acid mine tailings occur in coal and sulfide mining districts
      Acidic water kills many plants, absorbs dangerous levels of heavy metals
      Asbestos (from chain silicate minerals) causes cancer risk

Organic compounds--pesticides, herbicides, oils, vinyl chloride, PBC's, and many others.
      Most of these eventually break down into non-harmful substances, but often very slowly.

Oxygen-demanding waste--measured in Biochemical Oxygen Demand (BOD), suffocates aquatic life
      Sources: dead organic matter (leaves, etc.), sewage, fertilizer, agricultural wastes
      Causes eutrophication of lakes and streams (lack of oxygen below the surface)
      Nitrate causes an additional problem for infants (blue baby syndrome)

Pathogenic organisms--bacteria and viruses transmitted through water supply
      Examples: cholera, typhoid, hepatitis, dysentery
      Vaccination and chlorination of drinking water have largely solved this problem.

Oil--oil floats on water, cuts off oxygen & sunlight, destroys feather/fur insulation
      Oils are most dangerous in high (visible) concentrations, such as oil spills.
      Residues can remain in sediments and effect benthic sea life for decades.

Radioactive waste--radioactive decay creates gamma rays that destroy cells and cause cancer
      Sources: uranium mines, uranium enrichment plants, power and weapon facilities

Thermal pollution--increase in water temperature can kill certain organisms
      Sources: thermal power plants (coal, nuclear, etc.), other industrial plants

Salt--salty water cannot be used for drinking or agriculture because of its osmotic effects
      Sources: salt-water intrusion in coastal wells, excessive evaporation in rivers & lakes
      (The U.S. has to desalinate Colorado River water for the Mexicans.)

Reversing the Damage

Surface streams and lakes flush out pollutants within days to years following pollution events.
Sediments must sometimes be dredged to remove toxins that cling to them indefinitely.

The groundwater system flushes much more slowly, and sometimes pollution is permanent.
Heavy metals can be immobilized by injection of chemicals that promote precipitation.
Certain microbes can be used to breakdown some organic compounds in the ground.
Removal of water for treatment followed by re-injection is the only option for many pollutants.
      Air stripping removes gasoline and light oils from contaminated water.
      Adjusting the acidity (pH) of the water solves some pollution problems.
      Salt can be removed through reverse osmosis, electrolysis, or evaporation.
      Activated charcoal removes certain organic compounds from water.
      Various filtering and chemical treatments are also available.

Composition of Earth's Atmosphere
78% Nitrogen (N₂), 44 million year residence time
21% Oxygen (O₂), 7 million year residence time
0.9% Argon (Ar), almost infinite residence time
0.03% Carbon Dioxide (CO₂), 4 year residence time
0.07% others constituents (methane, ozone, carbon monoxide, nitrogen oxides, sulfur oxides)
1-4% Water vapor (H₂O) (transient component, part of hydrologic cycle)

Global Warming and the Greenhouse Effect
Solar energy reaches the earth mostly in the form of visible light (0.4-0.7 microns)
35% of this visible light energy is reflected off of clouds, glaciers, oceans, and land
The other 65% is absorbed and thereby heats the earth's surface
Being cooler, the earth radiates off its energy as infrared light (5-20 microns)
Infrared light is absorbed and reradiated in all directions by "greenhouse gasses"
This "greenhouse effect" keeps the earth's surface 20º warmer than it would otherwise be
Greenhouse gases (water vapor, carbon dioxide, hydrocarbons, ozone, CFC's) increase the effect
Carbon dioxide level is increasing with burning of fossil fuels and deforestation.

Air Pollutants
Particulates (small suspended solids)--from combustion of fuels, salt flats, dust storms
Carbon monoxide (CO)--from incomplete combustion of carbon fuels
Nitrogen oxides (NO, NO₂, N₂O)--from bonding of N & O in air during combustion of fuels
Sulfur dioxide (SO₂)--mostly from burning of sulfur-rich coal
Volatile organics (mostly unburned hydrocarbons)--from fuel spillage & incomplete combustion
Ozone (O₃)--from accidental bonding of three oxygens during combustion of fuels
Chlorofluorocarbons (CFCs)--man-made refrigerants (from leaking air conditioners, aerosols)
Lead--used to be added to gasoline as an anti-knock compound but now outlawed
Radon--from radioactive decay of uranium in granites & other rocks, enters basements.
Peroxyacetylnitrate (PAN: CH₃OONO₂)--smog gas, a secondary pollutant generated from methane, nitrogen oxides, ozone, and diatomic oxygen combined with sunlight energy.

Acid Rain
SO₂ + H₂O >> H₂SO₄ (Sulfuric acid)--2/3 of the cause of Acid Rain
NO_x + H₂O >> HNO₃ (Nitric acid)--1/3 of the cause of Acid Rain

Wet deposition is when the acid leaves the air in rain.
Dry deposition is when the acid is directly deposited on the ground, lakes, or plants.

Acid rain is mostly a regional problem, occurring downwind of major industrial centers.

Effects of acid deposition
Buildings and monuments corrode much faster.

Fish and other organisms suffer in acid lakes and streams.  Their growth is retarded, their reproductive cycles and salt balance are disturbed, their skeletons are malformed, and mercury and aluminum are absorbed as poisons because they are more soluble in acidic water.

If humans experience chemical disruptions similar to fish, the added aluminum intake (from the ground, pipes, etc.) could increase cases of kidney disease and brain disorders such as senile dementia and Alzheimer's and Parkinson's diseases.

Plant growth is drastically stunted, and under severe acid conditions forests can decay away (such as those in Germany).  Crop yields can also be drastically reduced.

Stratospheric Ozone Depletion
O₂ + UV >> O + O     UV radiation from sun breaks up O₂ in the Stratosphere
O₂ + O >> O₃             Most single oxygen atoms joins O₂ molecules to form ozone
If the ozone layer were brought down to surface pressure, it would be only 0.1 inch thick.

Nitrogen Oxides
NO + O₃ >> NO₂ + O₂     Nitrogen oxide destroys ozone molecules
NO₂ + O >> NO + O₂       Nitrogen dioxide destroys free oxygen atoms
NO is produced naturally and is destructible, but exhausts and shock waves of supersonic transports & rockets create it right in the ozone layer.  It is estimated that 500 continuously-operating supersonic transports would deplete the ozone layer by 16% in the northern hemisphere and 8% in the southern hemisphere.

Chlorine
Cl + 2O₃ >> Cl + 3O₂       Each chlorine atom continuously breaks down ozone.
Chlorine, being an element, is essentially indestructible, so it poses a long-term threat.  It is introduced into the atmosphere in CFCs, methyl chloride, and carbon tetrachloride.  By 1974, over a million metric tons of freon were being released into the atmosphere each year.  CFCs stay in the troposphere between 40 and 150 years, but it takes them 15 years to reach the ozone layer.  This delay means that the effect is not seen until long after the damage is done.  A 2% decrease in stratospheric ozone has already been observed, and the freon released so far should eventually cause a 20% decrease.  In 1974 the U.S. outlawed CFCs in aerosol sprays, but other countries continue to use it.  The Montreal Protocol called for halving the use of CFCs by 2000.  By the London conference in 1989, 66 countries had agreed to sign the protocol and 11 more were seriously considering it.  We are now moving toward elimination of CFCs in air conditioners.

Surface Water Law
Riparian Doctrine--land owners bordering on a water body have rights to the water
      One owner's use of the water should not interfere with use by other owners.
      This doctrine works well in England & eastern U.S. where water is generally plentiful.
Prior Appropriation--earliest users of a water source have top priority in times of shortage
      Primary users often waste water in order to retain their historic rights to it.
California Doctrine--the State decides how water should be used and redistributed.
Beneficial use hierarchy: domestic supply, hydropower, irrigation, industry

Ground Water Law
Rule of Capture (English Rule)--land owners can extract all the groundwater they want.
Rule of Reasonable Use (American Rule)--water use should not deprive use by neighbors.
California Rule--land owners have rights to an aquifer in proportion to their property size.

Mineral Rights
1872 Mining Law--prospectors could claim rights to mineral deposits & buy the land cheaply.
Mineral Leasing Act of 1920--land could be temporarily leased for extraction, royalties required.
Outer Continental Shelf Lands Act of 1953--regulation of seabed mining similar to Act of 1920.
Surface Mining Control and Reclamation Act of 1977--coal mine areas must be restored.

Ownership of the Ocean
1700--coastal countries have exclusive control out to one league (3 miles) from shore.
1958 1st Law of the Sea--seabed mineral and energy rights belong to the nearest country.
1982 U.N. Conference--coastal countries have exclusive rights to 12-mile Territorial Sea and a 200-mile Exclusive Economic Zone (EEZ).  U.S. did not ratify but claimed its EEZ.
1994 U.N. Conference--resolution of seabed mining issues has brought U.S. closer to approval.

Ownership of Antarctica
Argentina, Australia, Chile, France, New Zealand, Norway, and U.K. made conflicting claims.
The 1961 Antarctica Treaty set 1) dismissed all territorial claims, 2) banned military activities and nuclear waste disposal, and 3) called for preserving the indigenous flora and fauna.
1988 Regulation of Antarctic Mineral Resources Act--requires environmental impact statements and approval of an international supervisory commission
1990 Antarctic Protection Act--U.S. law preventing Antarctic mining by U.S. companies
      This is perhaps the only case where the U.S. has taken a lead to oppose exploitation!

Water Pollution Control
Refuse Act of 1899--prohibits dumping of refuse into navigable waters
Federal Water Pollution Control Act of 1956--restricted release of sewage
Clean Water Act of 1977--addresses all pollutants from point and non-point sources, called for elimination of pollutants by 1985 according to criteria set by EPA.
Protection of wetlands and groundwater are still being battled in the courts.

Air Pollution Control
Clean Air Act of 1963--beginning of regulatory efforts and agency standards
Air Quality Act of 1965--set standards for a variety of known pollutants
Clean Air Act of 1990--set standards higher than Montreal Protocol for elimination of CFCs and other ozone destroyers, called for reduction of over 200 known pollutants, required reduction of vehicle emissions and SO₂ emissions from coal power plants
International efforts to reduce air pollutants have been slow to materialize.
The Kyoto Treaty seeks to reduce worldwide CO₂ emissions, but the U.S. has not supported it.

Waste Disposal
Solid Waste Act of 1965--regulated mainly public solid waste disposal
Resource Conservation and Recovery Act of 1976--solid and hazardous waste management
      The EPA (and approved state agencies) sets standards and approves specific sites.
1984 Amendments--expanded regulation to smaller waste generators, established Superfund

Geologic Hazards Law
Zoning laws based of geologic hazard are often fought by land owners because it regulates their rights and devalues their land, but they have been upheld in courts for the public good.
California has been the most active state to set standards because of its population and risks.
California's Field Act requires earthquake-proof school buildings, has been very successful.
Los Angeles has regulated unstable hillside development, causing a big drop in property damage.
The Seismic Safety Bill of 1971 requires consideration of seismic hazards but sets no standards.
The Dam Safety Bill of 1972 only requires preparation of maps of potential flood areas.
The Alquist-Priolo Geologic Hazards Act of 1972 regulates building on active fault lines.
The Federal Flood Disaster Protection Act of 1973--requires floodplain zoning purchase of flood insurance by people living in flood-prone areas, encourages rebuilding after floods
A big problem with almost all geologic hazard laws is that they apply only to new construction.

Environmental Protection Agency
Established in 1970 to establish and enforce standards of pollution control
Can impose penalties up to $200,000 and pursue criminal sanctions in the courts

National Environmental Policy Act of 1969
NEPA requires an Environmental Impact Statement (EIS) including
1) Description of the proposed action, its purpose and need
2) A discussion of various alternatives
3) The anticipated environmental consequences
4) A list of agencies, organizations, and persons to receive a copy
A comment period follows release of the initial EIS, and inadequate EISs can be fought in court.
One problem is that the agency preparing the EIS is already supporting the proposed action.

Values
1) Value to humans vs. value to other species (endangered species act).
Preserving rain forests & salt marshes ("wastelands"), endangered species habitats.

2) Value to individual or local concerns vs. to humanity in the long term.
Preserving salt marshes to preserve fisheries, forests to recycle carbon dioxide.
Preserving the long-term productivity of soil through no till practices.

3) Pure economic priorities (capitalism) vs. community planning (socialism).
Should land always go to the highest bidder (property rights a basic American value).

Land used to be a virtually unlimited resource, but not anymore.

Possible land uses
Leave as is (wilderness areas, no road construction)
Urban (single house on large lot vs. high-rise buildings)
Agriculture
Highways/airports
Recreation areas (national parks)
Reservoirs
Mining areas
Energy acquisition (solar collectors, geothermal collectors, oil wells, coal mines)
Landfills
Short-term "slash and burn" uses

Multiple use land
Ball field and recharge basin
Agriculture and wind mills
Underground mining
Underground parking lots

Sequential use land
Forest > agriculture > urban (typical economic-driven conversion).
Abandoned mines as warehouses, waste dumps, or ponds (reclamation).

Land use incompatibilities
Building on land that is prone to natural disasters:
      Floods, landslides, coastal erosion, sinkholes, earthquakes, volcanic eruptions.
      (Expansive soils cause as much property damage as all natural disasters combined!)
Building pollution generators (industrial, agricultural) on prime groundwater recharge areas.
Construction in prime scenic areas.
Farming land that can't sustain farming for more than a year or two.
Building on land that cannot support structures over the long term (permafrost, shale, faults).

Land use priorities
Should less productive agricultural land be slated for urban uses?
Should prime endangered species habitat be left undisturbed?
Should land be set aside for parks and other community uses?
Or should economics alone determine what land is used for?
How much zoning regulation is the right amount?

Land planning strategies
Maps have long been used to assess current land use and potential use.
Computers use a grid system to indicate uses/hazards for each plot of land.
Different kinds of studies require different scales of evaluation.
Identification of geologic hazard areas, rock & soil type, special resource areas.

Alaskan Land Issues
Until recently over 95% of Alaska was federal land; some has now been transferred to the state.
In 1978 President Carter converted 1/3 of Alaska to National Park & other protected areas.
Economic resources: mining, petroleum, lumber, fisheries, tourism.
Karst is prime land for both lumber and spawning streams, but doesn't regrow well.
Mining and clear-cut logging are harmful to fisheries and tourism.

Factors
Bedrock & soil type
Slope steepness
Slope of bedrock layers
Location of active faults
Nearness to rivers, shorelines
Depth of water table
Presence of permafrost

Problems
Flood potential
Earthquake potential
Landslide potential
Coastal erosion
Expansive soil
Thawing soil
Unstable bedrock for dams, bridges, etc.

Panama Canal
Hindered by landslides in tilted bedrock & high rainfall area
Created a biogeographic connection between Gulf of Mexico & Pacific Ocean

Trans-Alaska Pipeline
Required insulation, raised towers, and zig-zags to deal with permafrost

Dam failures
Vaiont Reservoir, Italy filled by a giant landslide in 1963, killed 3000 people.
St. Francis Dam in California failed in 1928 due to gypsum dissolution, killed 200.
Lubrication of clays, differential settling, and faulting have also caused dam failures.

Expansive soils have caused more dollar damage than any other geologic hazard.