SCIENCE 8 Q2 Module 1. EARTHQUAKES AND FAULT | Types of Fault and Types of Stresses

Summary

In this educational video, Teacher Teammate welcomes students back to a science lesson on earthquakes and faults. The video covers key topics such as the causes of earthquakes, types of faults (normal, reverse, and strike-slip), and the stresses in the Earth's crust (compression, tension, shear, and confining). The lesson includes real-world examples, including a recent 5.3 magnitude earthquake in Luzon, Philippines, and uses models to explain geological movements. The video encourages students to stay engaged with future updates through subscriptions and notifications.

Takeaways

• 🌍 The lesson discusses earthquakes, faults, and types of stresses in the Earth's crust.
• 📊 Earthquakes occur due to sudden slips along faults, releasing energy that causes ground shaking.
• ⚙️ There are two main types of earthquakes: tectonic and volcanic, depending on the cause of the movement.
• 🔍 Faults are fractures or zones of fractures between two blocks of rock, allowing them to move relative to each other.
• 🔄 The three types of faults are: Normal Fault (where the hanging wall moves down), Reverse Fault (where the hanging wall moves up), and Strike-Slip Fault (where rocks slide past one another).
• ⚡ Strike-slip faults can be either left-lateral or right-lateral, depending on the direction of movement.
• 💥 The Philippines is located on the Pacific Ring of Fire, making it prone to frequent earthquakes and volcanic eruptions.
• 💫 The Earth’s crust is affected by four main types of stress: Compression, Tension, Shear, and Confining Stress.
• ⛰️ Compression stress pushes rocks together, potentially creating mountains, while tension stress pulls rocks apart, leading to separation.
• 🌪️ Shear stress causes rocks to move in opposite directions, which can result in earthquakes, and confining stress applies pressure from all directions, which can lead to sinkholes.

Q & A

What is the main topic of the lesson in the script?

The main topic of the lesson is earthquakes and faults, focusing on how movements along faults generate earthquakes and the different types of stresses in the Earth's crust.

What are the two types of earthquakes mentioned in the script?

The two types of earthquakes mentioned are tectonic earthquakes, caused by the movement of crustal plates, and volcanic earthquakes, which are associated with volcanic activity.

What is a fault according to the script?

A fault is described as a fracture or zone of fractures between two blocks of rock that allows them to move relative to each other. This movement can occur rapidly, causing an earthquake, or slowly in the form of creep.

What are the three types of faults explained in the script?

The three types of faults are: normal faults, reverse faults, and strike-slip faults. Each type describes different movements between the hanging wall and footwall.

How is a normal fault defined in the lesson?

A normal fault occurs when the hanging wall moves down relative to the footwall, typically due to the extension of the Earth's crust.

What characterizes a reverse fault?

A reverse fault occurs when the hanging wall moves up relative to the footwall, usually as a result of compression forces in the Earth's crust.

What is a strike-slip fault and what is an example provided in the script?

A strike-slip fault occurs when two blocks of rock slide past one another horizontally. The San Andreas Fault is provided as an example of a strike-slip fault.

What are the four types of stress in the Earth's crust as mentioned in the lesson?

The four types of stress in the Earth's crust are compression stress, tension stress, shear stress, and confining stress.

What is the difference between compression stress and tension stress?

Compression stress pushes rocks together, leading to thickening or shortening of the Earth's crust, while tension stress pulls rocks apart, causing them to separate.

What is the significance of shear stress in relation to earthquakes?

Shear stress occurs when rocks slide past one another in opposite directions, often along fault lines. This movement creates friction, which can lead to earthquakes.