Questions and Answers
What is an earthquake?
What is the focus of an earthquake?
The point within Earth where an earthquake originates.
What are faults?
A fracture in Earth along which movement has occurred.
Explain elastic rebound in the context of earthquakes.
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What is an aftershock?
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What is a foreshock?
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What is fault creep?
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Define seismology.
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What is a seismograph?
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Explain what a seismogram is.
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What are surface waves?
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What are body waves?
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What are Primary (P) waves?
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What are Secondary (S) waves?
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What is the epicenter of an earthquake?
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What is the Circum-Pacific Belt?
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Define intensity in the context of earthquakes.
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What does magnitude mean in terms of earthquakes?
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Explain the Modified Mercalli Intensity Scale.
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What is the Richter scale?
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What is the Moment Magnitude Scale?
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What is liquefaction?
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What are seismic sea waves (tsunami)?
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What is the crust of the Earth?
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Define the mantle.
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What is the lithosphere?
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What is the asthenosphere?
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What is the lower mantle?
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What is the core of the Earth?
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What is the outer core?
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What is the inner core?
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What is the Moho?
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What are refracted waves?
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What is a shadow zone?
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Study Notes
Earthquake Concepts
- Earthquake: A vibration of Earth from the rapid release of energy.
- Focus: The origin point of an earthquake beneath the Earth's surface.
- Faults: Fractures in Earth where movement has occurred.
Seismic Mechanics
- Elastic Rebound: Rocks deform and, upon breaking, release stored energy leading to an earthquake’s vibrations.
- Aftershock: A smaller earthquake that occurs following the main earthquake event.
- Foreshock: A smaller earthquake that typically occurs before a more significant earthquake.
Seismology and Measurement
- Seismology: The scientific study of earthquakes and seismic waves.
- Seismograph: An instrument used to record the vibrations produced by seismic waves.
- Seismogram: The output or the record generated by a seismograph.
Types of Seismic Waves
- Surface Waves: Seismic waves that travel along Earth’s surface, often causing the most damage.
- Body Waves: Seismic waves that move through the Earth's interior.
- Primary (P) Waves: Compression waves that push and pull rocks in line with their direction.
- Secondary (S) Waves: Waves that cause particles to shake perpendicular to their direction of travel.
Earthquake Location and Impact
- Epicenter: The surface point directly above the earthquake's focus.
- Circum-Pacific Belt: The major zone where most earthquakes occur globally.
- Intensity: A measure of shaking at a specific location based on damage.
- Magnitude: The total energy released during an earthquake.
Measurement Scales
- Modified Mercalli Intensity Scale: Rates shaking and damage variances across locations.
- Richter Scale: A logarithmic scale from 1 to 10 used to quantify earthquake energy release.
- Moment Magnitude Scale: A more precise measure based on fault displacement and energy estimation.
Geological Effects
- Liquefaction: A phenomenon where shaking causes wet soil to act like a liquid.
- Seismic Sea Waves (Tsunami): Water waves generated by seismic events, volcanic activity, or landslides.
Earth Layers
- Crust: The thin outer layer of Earth.
- Mantle: The rocky layer beneath the crust, approximately 2900 kilometers thick.
- Lithosphere: The cool and rigid layer that includes the crust and uppermost mantle.
- Asthenosphere: The soft layer under the lithosphere where lithospheric plates move.
Core Structure
- Lower Mantle (Mesosphere): Rigid and brittle layer constituting 80% of Earth’s material, located between 670-2900 km depth.
- Core: The central part of Earth made up of iron and nickel.
- Outer Core: A liquid layer within the core, characterized by mobile properties.
- Inner Core: A solid metallic sphere made primarily of nickel and iron.
Geophysical Boundaries
- Moho: The boundary separating the crust from the mantle.
- Refracted Waves: Waves in shallow water that slow down, bend, and align with underwater contours.
- Shadow Zone: An area between 105 and 140 degrees from an earthquake epicenter where direct P waves are absent due to refraction through the Earth's core.
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Description
Test your knowledge of key Earth Science terms with this quiz covering Chapter 8 definitions. Each term is accompanied by a concise definition, helping you reinforce your understanding of earthquakes and geological processes.