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Earth Systems Science Final Fall 24 Questions
with Detailed Verified Answers
What is an earthquake? Under what circumstances do most large earthquakes occur?
Explain why and how earthquakes occur, according to the elastic rebound hypothesis.
Why is there an upper limit on the intensity of earthquakes?
Ans: An earthquake is a sudden shaking of the ground, caused by the movement of
tectonic plates or the release of stress in the Earth's crust. Most large earthquakes
occur along faults, especially at plate boundaries, like subduction zones, transform
faults, and rifting zones.
The elastic rebound hypothesis explains earthquakes by suggesting that stress builds
up in the crust due to plate movement. When the stress exceeds the strength of the
rocks, they rupture and release energy as seismic waves. Afterward, the rocks "snap
back" to their original shape.
There's an upper limit to earthquake intensity because of the strength of rocks and the
size of faults. Once the stress exceeds the rock's strength, it ruptures, and there's a
physical limit to how much stress can accumulate before this happens.
What is the relationship between an earthquake's focus and its epicenter?
Ans: The focus is the point inside Earth where an earthquake starts, and the epicenter
is the point on the surface directly above it.
How are faults, hypocenters, and epicenters related?
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Ans: A fault is a fracture where rocks move, the hypocenter is the point inside Earth
where an earthquake starts, and the epicenter is directly above it on the surface.
How are seismic waves recorded and measured? What is the difference between a
seismograph and a seismogram? Describe the principle of a seismograph.
Ans: A seismograph detects ground motion, and a seismogram is the recorded wave
pattern. It works on the principle of inertia, where a stationary mass moves relative to
the ground.
How do scientists use seismic waves to determine the location of an earthquake?
Describe the process.
Ans: P-waves (faster) and S-waves (slower) reaching seismographs to calculate the
distance to the earthquake.
What type of faults tend to produce the most destructive earthquakes?
Ans: Reverse faults and thrust faults, common at convergent boundaries, tend to
produce the most destructive earthquakes due to the large amounts of energy
released.
Describe the important features of the Richter magnitude scale, the seismic moment
magnitude scale, and the modified Mercalli intensity scale, and comment on the
differences between them.
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Ans: The Richter scale measures magnitude based on seismic wave amplitude, suited
for small quakes. The seismic moment magnitude scale measures total energy
released, for all quake sizes. The Modified Mercalli scale assesses earthquake effects on
people and structures.
What are reflection and refraction, and how do they help scientists determine what's
insterm-6ide Earth?
Ans: Reflection occurs when seismic waves bounce off boundaries, and refraction
happens when they bend as they pass through different materials.
How did Earth acquire its layered structure?
Ans: Earth's layered structure formed during its early molten state, when denser
materials sank to form the core, and lighter materials rose to form the mantle and crust
through a process called differentiation.
Briefly describe how seismic waves are used to probe Earth's interior
Ans: Seismic waves change speed and direction based on the materials they pass
through. By analyzing their reflection and refraction, scientists can map Earth's layers
and determine their composition.
How do continental crustal and oceanic crust differ?
Ans: Continental crust is thicker, less dense, and made mostly of granite, while oceanic
crust is thinner, denser, and primarily composed of basalt.
Contrast the physical makeup of the asthenosphere and the lithosphere
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Ans: The lithosphere is rigid, brittle, and includes the Earth's crust and uppermost
mantle. The asthenosphere is softer, more ductile, and located beneath the
lithosphere, allowing it to flow slowly.
How are Earth's inner and outer cores different? How are they similar?
Ans: The inner core is solid, made of iron and nickel, due to high pressure, while the
outer core is liquid, also composed of iron and nickel, because of lower pressure. Both
are at Earth's center.
Earthquakes can cause damage in many ways; name and briefly describe four or more.
Ans: Shaking: Damages buildings.
Surface Rupture: Cracks the ground.
Liquefaction: Buildings sink.
Tsunamis: Coastal flooding.
Landslides: Triggered by shaking.
Can scientists predict when and where earthquakes will occur? How can scientists
forecast earthquakes?
Ans: Scientists cannot predict exact times or locations of earthquakes. However, they
can forecast earthquake likelihood based on fault zones, historical data, and seismic
activity patterns.
List the major differences between P. S. and surface waves
© Get it right 2025 Getaway - Stuvia US All rights reserved
Earth Systems Science Final Fall 24 Questions
with Detailed Verified Answers
What is an earthquake? Under what circumstances do most large earthquakes occur?
Explain why and how earthquakes occur, according to the elastic rebound hypothesis.
Why is there an upper limit on the intensity of earthquakes?
Ans: An earthquake is a sudden shaking of the ground, caused by the movement of
tectonic plates or the release of stress in the Earth's crust. Most large earthquakes
occur along faults, especially at plate boundaries, like subduction zones, transform
faults, and rifting zones.
The elastic rebound hypothesis explains earthquakes by suggesting that stress builds
up in the crust due to plate movement. When the stress exceeds the strength of the
rocks, they rupture and release energy as seismic waves. Afterward, the rocks "snap
back" to their original shape.
There's an upper limit to earthquake intensity because of the strength of rocks and the
size of faults. Once the stress exceeds the rock's strength, it ruptures, and there's a
physical limit to how much stress can accumulate before this happens.
What is the relationship between an earthquake's focus and its epicenter?
Ans: The focus is the point inside Earth where an earthquake starts, and the epicenter
is the point on the surface directly above it.
How are faults, hypocenters, and epicenters related?
© Get it right 2025 Getaway - Stuvia US All rights reserved
,Click here for more: Scholars nexus
Ans: A fault is a fracture where rocks move, the hypocenter is the point inside Earth
where an earthquake starts, and the epicenter is directly above it on the surface.
How are seismic waves recorded and measured? What is the difference between a
seismograph and a seismogram? Describe the principle of a seismograph.
Ans: A seismograph detects ground motion, and a seismogram is the recorded wave
pattern. It works on the principle of inertia, where a stationary mass moves relative to
the ground.
How do scientists use seismic waves to determine the location of an earthquake?
Describe the process.
Ans: P-waves (faster) and S-waves (slower) reaching seismographs to calculate the
distance to the earthquake.
What type of faults tend to produce the most destructive earthquakes?
Ans: Reverse faults and thrust faults, common at convergent boundaries, tend to
produce the most destructive earthquakes due to the large amounts of energy
released.
Describe the important features of the Richter magnitude scale, the seismic moment
magnitude scale, and the modified Mercalli intensity scale, and comment on the
differences between them.
© Get it right 2025 Getaway - Stuvia US All rights reserved
,Click here for more: Scholars nexus
Ans: The Richter scale measures magnitude based on seismic wave amplitude, suited
for small quakes. The seismic moment magnitude scale measures total energy
released, for all quake sizes. The Modified Mercalli scale assesses earthquake effects on
people and structures.
What are reflection and refraction, and how do they help scientists determine what's
insterm-6ide Earth?
Ans: Reflection occurs when seismic waves bounce off boundaries, and refraction
happens when they bend as they pass through different materials.
How did Earth acquire its layered structure?
Ans: Earth's layered structure formed during its early molten state, when denser
materials sank to form the core, and lighter materials rose to form the mantle and crust
through a process called differentiation.
Briefly describe how seismic waves are used to probe Earth's interior
Ans: Seismic waves change speed and direction based on the materials they pass
through. By analyzing their reflection and refraction, scientists can map Earth's layers
and determine their composition.
How do continental crustal and oceanic crust differ?
Ans: Continental crust is thicker, less dense, and made mostly of granite, while oceanic
crust is thinner, denser, and primarily composed of basalt.
Contrast the physical makeup of the asthenosphere and the lithosphere
© Get it right 2025 Getaway - Stuvia US All rights reserved
, Click here for more: Scholars nexus
Ans: The lithosphere is rigid, brittle, and includes the Earth's crust and uppermost
mantle. The asthenosphere is softer, more ductile, and located beneath the
lithosphere, allowing it to flow slowly.
How are Earth's inner and outer cores different? How are they similar?
Ans: The inner core is solid, made of iron and nickel, due to high pressure, while the
outer core is liquid, also composed of iron and nickel, because of lower pressure. Both
are at Earth's center.
Earthquakes can cause damage in many ways; name and briefly describe four or more.
Ans: Shaking: Damages buildings.
Surface Rupture: Cracks the ground.
Liquefaction: Buildings sink.
Tsunamis: Coastal flooding.
Landslides: Triggered by shaking.
Can scientists predict when and where earthquakes will occur? How can scientists
forecast earthquakes?
Ans: Scientists cannot predict exact times or locations of earthquakes. However, they
can forecast earthquake likelihood based on fault zones, historical data, and seismic
activity patterns.
List the major differences between P. S. and surface waves
© Get it right 2025 Getaway - Stuvia US All rights reserved
