Download EAPS 106 Review Questions: Earth's Structure, Plate Tectonics, and Earthquakes and more Exams Geography in PDF only on Docsity!
EAPS 106 โ Review Questions
Why the outer core is a liquid, but the hotter inner core is solid
- โ โ Because the inner core is under more pressure
What a passive plate margin is - โ โ a boundary between
continental crust and oceanic crust that is not a plate boundary
What a supercontinent is - โ โ one big continent with
most or all of the land mass
What an asperity is - โ โ rough spots along the fault
prevent the fault from sliding until they are broken
What caused the high topography of the Himalayas and Tibet -
โ โ India colliding into Asia during continental drift and
creating the tallest mountains in the world (only time two continents collided)
What drives plate tectonics - โ โ Convection in the Earth's
solid-state mantle drives plate tectonics (bottom surface is hot and top surface is cold)
Why the US Geological Survey believes there is a high seismic
hazard in the midwest - โ โ Three of the largest
earthquakes to occur in the contiguous U.S. happened in the midwest.
How GPS is used to predict how big the next earthquake in a region is likely to be - โ โ GPS measurements enable us
to measure slip deficit rates, the amount an earthquake will need to slip in order to reduce elastic stress build-up.
How many seismograms are required to locate an earthquake - โ โ 3
How movies generally and incorrectly depict earthquakes - โ
โ Having faults open a gap during earthquakes, buildings
swaying and collapsing (they pancake)
Why earthquakes are difficult to predict - โ โ The time
and magnitude of earthquakes on any fault is highly variable,
How the Earth acquired its internal heat. - โ โ planetary
accretion: Heat of collisions plus radioactive decay leads new planets to be molten (melted) inside,
How we know that our magnetic field has reversed itself many times - โ โ In the 1960s, we discovered magnetic
lineations on the seafloor that reveal how ocean crust is created at and then moves away from "spreading centers" (also called mid-ocean ridges).
Crystals in lava record the direction to the magnetic poles at the time of each eruption.
Know why the interior of the Earth is layered. - โ โ
planetary accretion: Heat of collisions plus radioactive decay leads new planets to be molten (melted) inside, which leads to differentiation as heavier elements sink to form a core and lighter elements rise to form a crust and mantle.
The components required for Earth's magnetic field - โ โ
Earth's liquid iron outer core provides all of the elements necessary to generate a very strong magnetic field (The
electrical current comes from motion of the electrical conducting liquid iron as the outer core convects. Convection in the outer core combined with the spin of the planet drives the liquid iron into elongated spirals that act as coils. Those coils spiral around more liquid iron, thus greatly increasing the strength of the magnetic field.
The consequences of losing our magnetic field - โ โ
compasses will be crazy
Aurora might be seen everywhere at night
More charged particles on Earth that lead to power outages and broken satellites
Migratory animals might have difficulties
NO MASS EXTINCTIONS
The importance of a proper foundations and what liquefaction is
- โ โ Buildings can fall over during an earthquake due to
liquefaction, where shaking temporarily turns wet sediments into slush. (quick sand). Solution to liquefaction: drive pilings thru the sediments into bedrock
1964 Alaska quake energy was like 150,000 atom bonds (9.2)
The percent chance of avoiding collapse during an earthquake that California building codes require - โ โ 90% of
avoiding collapse
The problem with earthquake precursors - โ โ
Foreshocks and aftershocks are just earthquakes associated with a bigger mainshock. Foreshocks are smaller earthquakes that sometimes occur before a bigger mainshock. Most times earthquakes are not preceded by foreshocks
The relationship between the biggest magnitude earthquakes and the deadliest - โ โ The biggest earthquakes (M8+)
are not generally the deadliest โ it is often M7+ that occur in heavily populated regions with poor building practices.
The settings (type of plate boundaries, direction of relative plate motion) in which thrust, normal, and
strike-slip faults occur - โ โ Thrusting Faults: Occurs in
compressional settings like subduction zones. (he fault is at an angle so that slip along the fault enables the region to shorten.
Normal Faulting: Occurs in extensional settings
like mid-ocean ridges. (The fault is at an angle so that slip along the fault enables the region to lengthen.)
How an earthquake early warning system works - โ โ
Concept: Seismic waves travel slower than the speed of light. Therefore, one can detect an earthquake and communicate a warning ahead of the shaking.
How do the plates deform before compared to during a
subduction zone earthquake - โ โ Before the earthquake,
subduction of the Pacific Plate was pushing Japan to the west, compressing it. During the earthquake Japan rebounded back to the east, releasing that stored energy.
How earthquake magnitudes are related to the relative
magnitude of shaking - โ โ Every whole number increase
in magnitude, the amplitude of shaking goes up by a factor of 10
Strike-slip (transform) Faults: Occurs in settings where plates slide laterally past each other. (The fault is vertical (no headwall or footwall) The crust neither lengthens nor shortening)
Rayleigh Waves: Up-down motion like an
ocean wave. Travels only along the surface of a solid or liquid. Surface waves are the last to arrive, but cause the most deformation
Things to do to minimize earthquake deaths, especially your own - โ โ If indoors (but not in a third-world country)
- Stay indoors
- Drop to the ground; take cover under a table.
- Stay away from glass and anything that could fall.
- Use a doorway for shelter only if you know it is a strongly
supported, loadbearing doorway.
- DO NOT use the elevators.
If indoors (in a third-world country)
- Get out of the building as fast as possible
If outdoors
- Stay outdoors, move away from buildings.
What a mid-ocean ridge, a subduction zone, and a transform plate boundary are - โ โ Mid-Ocean Ridges: referred to
as divergent margins since the plates move away each other
Subduction Zone: Oceanic lithosphere is recycled back into the mantle at "subduction zones", which enables continents to drift over the ocean basins
referred to as convergent margins since the plates move toward each other, where most earthquakes and volcanoes occur.
Transform Plate Boundary: where two plates laterally slide past each other.
What earthquake intensity (Mercalli Scale) measures and the factors that influence it - โ โ Mercalli Intensities: The
shaking that people and buildings feel. Based on felt reports.
Influenced by the magnitude of an earthquake, its
distance, and the local geology
What elastic rebound and stick-slip behavior are - โ โ
Elastic Rebound: the crust bends like rubber
Why diagonal beams help buildings be more resistant to earthquakes - โ โ Diagonal beams provide resistance to
the
shearing that often causes buildings to collapse
What forecasting earthquake probabilities is based on - โ โ
While we can't predict the place and time of
earthquakes, we can use our knowledge of
past earthquakes to estimate the probability of future earthquakes.
What lithosphere and asthenosphere are - โ โ
Lithosphere: Strong outer shell of the Earth consisting of the crust and uppermost (coldest, strongest) layer of the mantle. (breaking = tectonic plates)
Asthenosphere: Weakest layer of the mantle (flows readily) and underlies the lithosphere. (allows tectonic plates to move, silly putty)
What the Wilson cycle is - โ โ The Wilson Cycle is
describes how continents break up and then rejoin
