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