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UCSB Earth 20 Midterm Exam Study
Guide Solutions
Processes - ANSWER✔✔-Physical, chemical, and biological ways in which events
affect Earth's surface
Internal processes - ANSWER✔✔-Come from forces within Earth (plate tectonics) and result of internal
energy from earth
External processes - ANSWER✔✔-Come from forces on Earth's surface (atmospheric effects, energy from
the Sun)
Hazard - ANSWER✔✔-Natural process or event that is a potential threat to human life or property
Disaster - ANSWER✔✔-Hazardous event that occurs over a limited time in a defined area
Criteria for disaster - ANSWER✔✔-1) Ten or more people killed
2) 100 or more people affected
3) State of emergency is declared
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4) International assistance is requested
Catastrophe - ANSWER✔✔-Massive disaster that requires significant amount of money or time to
recover
Geologic Conditions - ANSWER✔✔-Govern the type, location, and intensity of natural processes
Tectonic cycle - ANSWER✔✔-Refers to large scale processes that deform Earth's crust and produce
landforms. Driven by forces within Earth (internal energy). Involves the creation, destruction, and
movement of tectonic plates
Rock cycle - ANSWER✔✔-Rocks are aggregates of one or more minerals. It is the recycling of earth
materials and rocks are classified according to how they were formed in the rock cycle
Igneous rocks - ANSWER✔✔-Form from crystallization of magma
Sedimentary rocks - ANSWER✔✔-Rocks are weathered into sediment by wind and water and deposited
sediment undergoes lithification
Metamorphic rocks - ANSWER✔✔-Rocks are changed through extreme heat, pressure, or chemically
active fluids
Hydrologic cycle - ANSWER✔✔-Movement of water between atmosphere and oceans and continents
driven by solar energy
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Processes of hydrologic cycle - ANSWER✔✔-Evaporation, precipitation, surface runoff, and subsurface
flow
Residence time - ANSWER✔✔-Estimated average that a drop of water spends in any compartment
Biogeochemical cycle - ANSWER✔✔-Transfer of chemical elements through a series of reservoirs
(Atmosphere, lithosphere, hydrosphere, biosphere)
Forecast vs Prediction - ANSWER✔✔-Prediction: Specific date, time, and magnitude of event
Forecast: Range of probability for event
Risk Analysis - ANSWER✔✔-Risk = (probability of event) x (consequences)
Consequences - ANSWER✔✔-damages to people, property, economics, etc.
Acceptable risk - ANSWER✔✔-the amount of risk that an individual or society is willing to take
Geoid - ANSWER✔✔-The shape that the surface of the oceans would take under the influence of Earth's
gravity and rotation alone
Outer core - ANSWER✔✔-Liquid, 2,000 km (1,243 mi.) in thickness • Composition similar to inner core •
Density (10.7 g/cm3)
Inner core - ANSWER✔✔-Solid, High Temperature, Composed of iron (90 percent by weight) and other
elements (sulfur, oxygen, and nickel)
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Mantle - ANSWER✔✔-Solid, 3000km thick, Composed of iron- and magnesium-rich silicate rocks
Crust - ANSWER✔✔-Outer rock layer of the earth, Moho discontinuity (separates lighter crustal rocks
from from more dense mantle)
Lithosphere - ANSWER✔✔-cool, strong outermost layer of Earth (crust and upper mantle) with crust
embedded on top
Asthensophere - ANSWER✔✔-Below lithosphere, Hot, soft/ductile slowly flowing layer of weak rock.
Higher water content and hotter
Continent crust - ANSWER✔✔-Less dense, thicker, and older and typically composed of granite
Oceanic crust - ANSWER✔✔-More dense, younger, thinner and typically composed of basalt
Convection - ANSWER✔✔-Earth's internal heat causes magma to heat up and become less dense.
-less dense magma rises
-cool magma falls back downward
P-waves - ANSWER✔✔-travels fastest, compressional waves, can travel through solids, liquids and gasses
S-waves - ANSWER✔✔-Secondary waves, shearing waves (vertical or horizontal) move up/down, doesn't
move through liquid
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