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GEOL 120: EXAM 1
Environmental Geology |
Application of geologic principles and techniques to entire spectrum of interactions between people and the environment. |
Geohazard |
Geologic phenomenon representing common risk to life and property. |
Carrying capacity |
The largest population that an area can support. |
Population growth rate |
The birth rate of a population minus the death rate
|
Doubling time |
The number of years needed to double a population, assuming a constant rate of natural increase. |
Lithosphere |
Earth's solid, rocky outer layer (Pedosphere= Young part of the lithosphere) |
Hydrosphere |
All of Earth's water. (Cryosphere=Ice)
|
Atmosphere |
A mixture of gases that surrounds a planet, such as Earth.
|
Biosphere |
All life forms on Earth. (Anthrosphere= Humans) |
Cycle |
A series of events that happen over and over again.
|
Rock Cycle |
a repeated series of events by which rock gradually and continually changes between igneous, sedimentary, and metamorphic forms |
Hydrologic Cycle |
The cycle through which water in the hydrosphere moves; includes such processes as evaporation, precipitation, and surface and groundwater runoff.`
|
Tectonic Cycle |
the cyclic production and destruction of lithosphere through slow movement of tectonic plates. |
Zero population growth |
when the birth rate equals the death rate.
|
J-curve |
a growth curve that depicts exponential growth.
|
Limiting resources |
any environmental resource that, because it is scarce or at unfavorable levels, restricts the ecological niche of an organism. |
Sustainability |
Develop or use of resources in such a way that future generations can have a fair share of Earth's resources and inherit a quality environment. |
Earth Systems Science |
The study of Earth systems and the systems in space, An emerging science of earth as a complete entity (physical, chemical, biological, planetary change, etc.)
-Spear- Headed by NASA.
-Broader view than traditional Earth Science.
-Geology: "process-response oriented" science; provides historical perspective on temporal scales of change and spatial scale focus. |
Global change |
The changes produced in the Earth system as a result of human activities.
|
Global Warming |
An increase in the average temperature of the earth's atmosphere (especially a sustained increase that causes climatic changes). |
Greenhouse effect |
Process by which atmospheric gases trap heat close to Earth's surface and prevent it from escaping into space.
|
Open/closed system |
An open system is susceptible to outside influences. A closed system, on the other hand, is not.
|
Threshold effect |
Systems resist change until overwhelmed, followed by sudden change.
|
Oligotrophic |
a condition of a lake or other body of water characterized by low nutrients, low productivity, and high oxygen levels in the water column. |
Uniformitarianism |
Processes active today have been active throughout geologic time, but magnitude and frequency of processes are subject to natural and artificial change (including rate).
-Paraphrased as "present is key to past." (unless evidence suggests otherwise.)
|
Magitude |
the amount of energy released by the earthquake. |
Frequency |
How often a piece of data occurs. |
Frequency - Magnitude concept |
Inverse Relationships between frequency of event and magnitude of event. |
Feedback |
Condition where the output of system is also imput to the same system.
|
Positive feedback |
(Vicious Cycle) outcome of one event change amplifies next event.
|
Negative feedback |
outcome of one change decreases process for next event, eventually approaching "steady state." (Never fully reached) |
Fault |
A fracture on which one body of rock slides past another. |
Earthquake |
The shaking that results from the movement of rock beneath Earth's surface. |
Stress |
The push, pull, or shear that a material feels when subjected to a
force; formally, the force applied per unit area over which the force acts. |
Strain |
The change in shape of an object in response to deformation (i.e., as
a result of the application of a stress). |
Focus |
Point at the depth where the rocks ruptured to produce earthquakes; place where quake waves originate |
Hypocenter |
it is also known as focus. It is the actual location or starting point of an eathqeake underground. |
P and S waves |
P waves travel faster and through any kind of material; S waves are slower and travel only through solids. P-Push and pull motion. S- Up and down motion.
|
Surface waves |
seismic waves that travel along the Earth's surface |
Epicenter |
Point on Earth's surface directly above the focus of an earthquake |
Siesmograph |
the instrument that detects, measures, and records the energy of earthquake vibrations |
Siesmogram |
a tracing of earthquake motion that is created by a seismograph |
Resonance |
A vibration of large amplitude produced by a relatively small vibration near the same frequency of vibration as the natural frequency of the resonating system
|
Liquifaction |
Occurs when wet soil acts more like a liquid during an earthquake
|
Tsunami |
A huge destructive wave (especially one caused by an earthquake)
|
Paleoseismology |
The study of prehistoric earthquakes.
|
Seiche |
Rhythmic movement in a body of water caused by ground motion. |
Pahoehoe |
A lava flow with a surface texture of smooth, glassy, rope-like
ridges.
|
Aa |
A lava flow with a rubbly surface |
Lahar |
A thick slurry formed when volcanic ash and debris mix with water,
either in rivers or from rain or melting snow and ice on the flank of a volcano.
|
Nuee Ardente |
Pyroclastic flow |
Maar |
A maar is a broad, low-relief volcanic crater that is caused by a phreatomagmatic eruption, which is an explosion caused by groundwater coming into contact with hot lava or magma. |
Tephra |
Unconsolidated accumulations of pyroclastic grains.
|
Pyroclastic |
Fragmented material that sprayed out of a volcano and
landed on the ground or sea floor in solid form. |
Plinian Eruption |
also known as Vesuvian eruptions, are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in AD 79. Plinian eruptions are marked by columns of gas and volcanic ash extending high into the stratosphere, a high layer of the atmosphere. |
Lava Dome |
A dome-like mass of rhyolitic lava that accumulates above the
eruption vent.
|
Outgassing |
the release of a gas that was dissolved, trapped, frozen or absorbed in some material. |
Mafic |
A term used in reference to magmas or igneous rocks that arc relatively poor in silica and rich in iron and magnesium. |
Felsic |
An adjective used in reference to igneous rocks that arc rich in elements forming feldspar and quartz. |
Caldera |
A large circular depression with steep walls and a fairly flat floor,
formed after an eruption as the center of the volcano collapses into the drained magma chamber below. |
Shield Volcano |
A subaerial volcano with a broad, gentle dome, formed
either from low-viscosity basaltic lava or from large pyroclastic sheets.
|
Fissure Flow |
A conduit in a magma chamber in the shape of a long crack through
which magma rises and erupts at the surface. |
Stratovolcano |
A large, cone-shaped subaerial voleano consisting of alter
nating layers of lava and tephra.
|
Cinder cone |
A subaerial volcano consisting of a cone-shaped pile of tephra
whose slope approaches the angle of repose for tephra. |
Palean Eruption |
These eruptions result from the collapse of an andesitic or rhyolitic lava dome, with or without a directed blast, to produce glowing avalanches or nuée ardentes, as a type of pyroclastic flow known as a block-and-ash flow. |
Icelandic eruption |
The Icelandic type is characterized by effusions of molten basaltic lava that flow from long, parallel fissures. Such outpourings often build lava plateaus.
|