EAS 210 - Midterm 2: Sample 1 Flashcards
What is the correct order of arrival at a seismograph station?
P-waves, S-waves, surface waves
Which of the following statements is false?
a. Liquids do not transmit S-waves.
b. P-waves travel more slowly in the outer core than in the lower mantle.
c. The shadow zone for P-waves is larger than for S-waves.
d. Seismic waves follow curved paths within the Earth.
The shadow zone for P-waves is larger than for S-waves
Which seismic waves are compressional?
P-Waves
The energy released by an earthquake of magnitude 8 is how many times greater than that of a magnitude 6 earthquake?
900
What scale is an earthquake’s observed effect on people and structures measured on?
Modified Mercalli Scale
What are earthquakes with foci deeper than 100 km associated with?
Convergent Plate Boundaries
Where do the majority of earthquakes occur?
The circum-Pacific belt
What is the epicenter of an earthquake?
The point on the surface above the focus.
According to the elastic rebound theory,
a. rocks will bend before they break
b. rocks will snap back to their original shape before faulting
c. rocks will break when their ability to deform has been exceeded
d. a and c
e. all of the above
e. all of the above
What was the Richter magnitude for the largest earthquake recorded on Earth?
9
Which Canadian province experiences the most earthquakes?
British Columbia
Two earthquakes have magnitudes of 6 and 7. Which of the following statements are true?
a. The second earthquake has a surface motion 10 times more than the first.
b. The second earthquake has an energy release 10 times more than the first.
c. The second earthquake has an energy release 30 times more than the first.
d. a and b
e. a and c
e. a and c
You are travelling from the coast to the deepest part of the ocean. In which sequence will you cross the following features?
Abyssal Plain | Continental Rise | Continental Shelf | Continental Slope |
Continental Shelf
Continental Slope
Continental Rise
Abyssal Plain
How does sonar measure the depth of the ocean?
Reflecting sound waves from the seafloor
Where is the thickest crust found?
Beneath large mountain belts
Which of the following statements about the Earth’s crust are true?
a. Oceanic crust is generally thicker and continental crust is thinner.
b. Oceanic crust is generally thinner and continental crust is thicker.
c. Oceanic crust may be thicker or thinner than continental crust.
d. oceanic and continental crust have exactly the same thickness.
b. Oceanic crust is generally thinner and continental crust is thicker.
Where is the youngest ocean crust found?
At the crest of mid-ocean ridges
When did the most recent geomagnetic reversal occur?
About 800,000 years ago
What happens to an igneous rock when it is heated up, exceeding the Curie temperature?
The rock becomes non-magnetic
What type of forces dominate at convergent plate boundaries?
Compressional
What did continent-continent convergence produce?
The Himalayas
Which of the following is a transform plate boundary?
a. East African Rift
b. East Pacific Rise
c. Mid-Atlantic Ridge
d. San Andreas Fault
e. Cascadia subduction zone
d. San Andreas Fault
What order are sea-floor spreading rates?
2 to 12 centimeters per year
Note: Keyword is centimeters
What are volcanic islands associated with?
Ocean-ocean convergent plate boundaries
At what depth does the boundary between the mantle and core lie? (Approximately)
3000 km
What is Earth’s core predominantly composed of?
Iron
How is heat primarily transported from the interior to the surface of Earth?
Convection
Approximately how thick is the lithosphere?
250 km
What is the geoid?
An irregular surface that has constant gravitational potential energy.
Observations that support the theory of plate tectonics include:
a. accurate measurements of place velocity with GPS instruments
b. the distribution of volcanic islands formed by hot spots
c. the global distribution of earthquake epicenters
d. the global distribution of active volcanoes
e. all of the above
e. all of the above
Where are braided streams found?
In a narrow gorge cut into bedrock
Which of the following is an erosional feature?
a. Alluvial Fan
b. Natural Levee
c. Point Bar
d. None of the Above
d. None of the Above
What is the discharge of a river measured in?
Cubic meters per second
What does it mean when a river meanders?
The flow is slowest on the inside of the meander and fastest on the outside.
Where is a cut bank found?
On the outside of a river meander
What is a fifty year flood?
A flood that occurs approximately every 50 years
What is the competence of a stream?
The maximum particle size that the stream can transport
Which of the following statements about floods is true?
a. In an upstream flood, the river flows upstream.
b. On a particular river, small floods occur more often than large floods.
c. On a particular river, large flood occur more often than small floods.
d. Regional floods impact a smaller area than flash floods.
e. In regional flood, the discharge rises more quickly than in a flash flood.
b. On a particular river, small floods occur more often than large floods.
What is the general term for sediment deposited by glaciers?
Drift
Approximately how many cycles of advance and retreat has the ongoing ice age included?
20
What is the boundary between regions of a glacier where accumulation and ablation occurs?
Equilibrium line
During the ice age a river valley was enlarged by an alpine glacier. What will be the shape of the resulting valley when the glacier melts?
U-Shaped
Which of the following statements is true?
a. Sea ice is composes of frozen fresh water.
b. An ice shelf is composed of frozen sea water.
c. An ice sheet is composed of frozen fresh water.
d. Both an ice shelf and sea ice are composed of frozen fresh water.
e. Both and ice shelf and sea ice are composed of frozen sea water.
c. An ice sheet is composed of frozen fresh water.
How does a glacier move downhill?
A combination of internal deformation of the ice, basal slip and deformation of sediments at the bed.
Which of the following types of mass movements has a significant airborne component?
a. fall
b. slump
c. spread
d. topple
a. fall
Which of the following slopes is the least stable?
a. One with horizontal sedimentary layers.
b. One with sedimentary layers dipping parallel to the slope.
c. One with sedimentary layers dipping perpendicular to the slope.
d. All are equally stable.
b. One with sedimentary layers dipping parallel to the slope.
What type of terrain is formed by landslides originating in volcanic collapse?
Hummocky
What is slide?
A form of mass wasting characterized by a coherent unit moving downhill.
What weather condition is most likely to cause landslides?
Heavy Rain
What is a fall?
A form of mass wasting characterized by the rapid vertical motion of material under the influence of gravity.
What is the approximate age of the Earth?
4,600,000,000 years
4.6 billion years old
A radioactive element has a half life of 5 million years. After 15 million years, what fraction of the parent atoms will remain?
1/8
A radioactive element has a half life of 20 years. A mineral grain contains 1/16 of the original parent atoms. How old is the grain?
80 years
Radioactive dating is being used to find the age of a granite sample. Sometimes, after crystallization, the granite undergoes metamorphism, and some daughter atoms are lost. The date obtained will be
Younger than the age of granite formation
What is the loss of an electron from a nucleus called?
Beta Decay
What is the loss of 2 protons and 2 neutrons from the nucleus called?
Alpha Decay
List the following time unites in the correct sequence. (Starting with the longest)
Eon | Epoch | Era | Period |
Eon, Era, Period, Epoch
The sequence of eons in Earth history is: (From oldest to youngest)
Archean | Hadean | Phanerozoic | Proterozoic |
Hadean, Archean, Proterozoic, Phanerozoic
