Earthquakes and Faults | Grade 8 Science DepEd MELC Quarter 2 Module 1

Summary

This video script educates viewers on earthquakes and faults. It explains the Philippine location along the 'Ring of Fire' and the concept of faults as breaks in the Earth's crust leading to significant displacement. The script uses activities to illustrate fault formation and earthquake generation, emphasizing the difference between focus and epicenter. It covers earthquake types, magnitude, and intensity, and concludes with practical safety tips for before, during, and after an earthquake.

Takeaways

• 🌏 The Philippines is situated along the Ring of Fire, a region around the Pacific Ocean known for frequent earthquakes and volcanic eruptions.
• 🏞️ Earthquakes are natural disasters that can cause significant destruction, challenging the ancient belief that the Earth is solid and steady.
• 🔍 Scientists have been diligently working on methods to predict earthquakes, although they cannot prevent them from happening.
• 📊 Earthquakes are linked to faults, which are fractures in the Earth's crust where significant movement occurs when the fault suddenly shifts.
• 🏗️ A fault is a fracture or discontinuity in the rock across which there has been considerable displacement due to rock mass movements.
• 🔧 Faults can produce earthquakes when the friction holding rocks together is overcome, causing a sudden slip.
• 📍 The point where an earthquake originates is called the focus, and the point directly above the focus on the Earth's surface is the epicenter.
• 📊 Earthquakes are measured by two scales: magnitude, which is the energy released at the focus, and intensity, which is the strength of shaking perceived at a location.
• 📈 The Richter scale is used to measure earthquake magnitude, while intensity is assessed by the effects and damage caused.
• 🏛️ Active faults are those that have moved in the past and are expected to move again, posing potential threats, while inactive faults no longer pose a threat.
• 🛠️ There are three main types of faults: normal faults where the hanging wall drops, reverse faults where the hanging wall moves up, and strike-slip faults where the walls move sideways.

Q & A

What is the Ring of Fire and why is the Philippines located along it?

The Ring of Fire refers to the region around the Pacific Ocean that is commonly hit by earthquakes and volcanic eruptions. The Philippines is located along the Ring of Fire, which makes it prone to these natural disasters.

What is an earthquake and why are they significant?

An earthquake is a sudden shaking or震动 of the ground caused by the breaking and shifting of underground rock. Earthquakes are significant because they can cause widespread destruction and are one of the most horrifying natural phenomena that humans can experience.

What is a fault and how is it related to earthquakes?

A fault is a break in the Earth's crust along which there has been significant movement. Earthquakes are associated with faults because they occur when a fault suddenly moves, causing the ground to shake.

How can one understand the concept of a fault through a simple activity?

One can understand faults by performing an activity involving two sheets of cardboard with sand poured along their boundary. When the cardboard is moved, a crack forms in the sand, and the lines are displaced, simulating a fault's movement.

What causes earthquakes to occur along faults?

Earthquakes occur along faults when energy from inside the Earth causes the ground to move. This is often described as 'stick and slip', where rocks are stuck together due to friction and then suddenly slip, generating an earthquake.

What is the difference between the focus and the epicenter of an earthquake?

The focus of an earthquake is the point within the Earth where the earthquake originates. The epicenter is the point on the Earth's surface directly above the focus.

How are the magnitude and intensity of an earthquake measured?

The magnitude of an earthquake is measured using the Richter scale and represents the entire energy released by the earthquake at its focus. The intensity of an earthquake is measured in terms of its geological effects and the damage it causes, and it is perceived as the strength of shaking felt by people in a certain locality.

What is the difference between a normal, reverse, and transcurrent fault?

A normal fault forms when the hanging wall drops down due to extensional forces. A reverse fault occurs when the hanging wall moves up due to compressional forces. A transcurrent or strike-slip fault has walls that move sideways, not up or down.

Why is it important to prepare for earthquakes even though they cannot be predicted?

It is important to prepare for earthquakes because, although they cannot be predicted, understanding what to do before, during, and after an earthquake can save lives and reduce damage.

What are some safety measures to take before, during, and after an earthquake?

Before an earthquake, prepare an emergency kit, know your emergency route, secure heavy objects, and prepare fire extinguishing equipment. During an earthquake, move away from windows and heavy objects, extinguish any fire, and take cover under a sturdy table. After an earthquake, grab your emergency kit, avoid using elevators, stay away from damaged buildings, and follow the same safety steps for aftershocks.