Causes and Types of Earthquakes

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Questions and Answers

What type of wave is characterized by side-to-side movement of the ground?

Love Waves

P Waves

Rayleigh Waves

S Waves (correct)

Which type of seismic wave travels more slowly and causes the most damage during an earthquake?

P Waves

S Waves

Surface Waves (correct)

Body Waves

What does the magnitude of an earthquake measure?

The total duration of the earthquake

The distance the waves travel

The intensity of shaking felt by people

The energy released at the source (correct)

Which seismic wave is known for causing horizontal shearing of the ground?

Love Waves Signup and view all the answers

How does intensity differ from magnitude in measuring earthquakes?

Intensity measures the effects at specific locations. Signup and view all the answers

What type of stress occurs when forces pull apart?

Tensive Stress Signup and view all the answers

Which type of fault is characterized by the rock above the fracture plane moving downwards?

Normal Fault Signup and view all the answers

Which fault type occurs when rocks on the 'uphill' side of an inclined plane rise above the other side?

Reverse Fault Signup and view all the answers

What is the term used for the sudden elastic rebound of previously stored energy in the context of earthquakes?

Elastic Rebound Theory Signup and view all the answers

Where is the epicenter of an earthquake located?

At the point of maximum damage on the Earth's surface Signup and view all the answers

Which type of stress involves forces that slide past each other?

Shear Stress Signup and view all the answers

What defines a strike-slip fault?

Rocks moving past each other laterally Signup and view all the answers

What happens at the focus of an earthquake?

Seismic waves are emitted in all directions Signup and view all the answers

What is the main cause of tectonic earthquakes?

Movement of tectonic plates Signup and view all the answers

Which type of earthquake is responsible for 95% of all earthquakes?

Tectonic earthquakes Signup and view all the answers

What are tremors primarily characterized by?

They are milder seismic vibrations Signup and view all the answers

What term is used to describe earthquakes caused by human activities?

Man-made earthquakes Signup and view all the answers

What drives the movement of tectonic plates?

Convection currents in the mantle Signup and view all the answers

Which of the following descriptions best characterizes stress in geological terms?

It is the force per unit area causing deformation Signup and view all the answers

What commonly results from the movement of tectonic plates over time?

Creation of faults at boundaries Signup and view all the answers

Volcanic earthquakes are typically caused by what process?

Vibrations from fluid movements within a volcano Signup and view all the answers

Study Notes

Earthquake Causes

Earthquakes are caused by the sudden release of energy in the Earth's crust.
Tectonic earthquakes are the most common type, caused by the movement of tectonic plates.
Volcanic earthquakes are associated with volcanic activity and are caused by magma movement.
Man-made earthquakes, also known as induced seismicity, can occur due to human activities like mining and fluid extraction.

Earthquake Types

Earthquakes are distinguished based on their origin and intensity.
Tremors are milder seismic vibrations compared to earthquakes.

Tectonic Plates

Tectonic plates are large pieces of the Earth's lithosphere, which consists of the upper mantle and crust.
These plates move slowly across the semi-fluid asthenosphere due to convection currents, gravity, and Earth's rotation.

Plate Boundaries

Tectonic plates meet at boundaries where they interact.
Interactions at these boundaries are categorized based on how plates move:
- Divergent: Plates move apart.
- Convergent: Plates collide.
- Transform: Plates slide past each other.

Stress and Strain

Stress: Force applied per unit area, causing deformation in rocks.
- Tensile Stress: Forces pull apart.
- Compressive Stress: Forces push together.
- Shear Stress: Forces slide past each other.
Strain: Deformation resulting from applied stress.
The gradual buildup and release of stress and strain is explained by the "elastic rebound theory."

Faults

A fault is a fracture or zone of fractures in the Earth's crust where rock movement has occurred.
The area directly above where two tectonic plates interact is called a fault.

Types of Faults

Normal Fault: Rocks above an inclined fracture plane move downward.
Reverse Fault: Rocks on the uphill side of an inclined fault plane move upward.
Strike-Slip Fault: Blocks of rock move past each other horizontally.

Focus and Epicenter

Focus: Point inside the Earth where an earthquake originates, releasing energy and creating seismic waves.
Epicenter: Point on the Earth's surface directly above the focus.

Seismic Waves

Seismic waves are energy waves that travel through the Earth due to an earthquake.
Body Waves: travel through the Earth's interior.
- P (Primary) Waves: Compressional waves, push and pull the ground.
- S (Secondary) Waves: Shear waves, move the ground side-to-side.
Surface Waves: travel along the Earth's surface.
- Love Waves: Cause horizontal shearing.
- Rayleigh Waves: Cause elliptical, rolling motion.

Earthquake Measurement

Magnitude: Measures the energy released at the earthquake's source.
Intensity: Measures the effects of an earthquake at specific locations, assessing shaking felt and damage.

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Description

Explore the fundamental causes and types of earthquakes in this quiz. Learn about tectonic movements, volcanic activities, and human-induced seismicity. Test your knowledge of tectonic plates and their interactions at boundaries.