SEISMIC WAVESEDITHA G. GONE

OBJECTIVES• Familiarize what are seismic waves

and how it moves the ground.

• Demonstrate the movement of each type of seismic waves.

• Promote team work and participation.

Answer directly in one complete sentence.1. What is a wave?2. Why do seismic waves differ from other waves like

sound waves?

Arrange the following labels to their corresponding location in the figure given below. DO NOT DRAW THE FIGURE. Simply write the label after the corresponding number of each location.

2

4 1

3EPICENTERFAULT

FOCUS

FAULT LINE

EARTH’S SURFACE

CRUST

ANSWER

1. What is an wave?Wave is a rhythmic disturbance that

carries energy without transporting matter from place to place.2. Why do seismic waves differ from other waves like sound waves?

Seismic waves differ from other waves like sound waves because it is the wave that carries the energy from beneath the ground during earthquakes.

QUIZ 2.19

ANSWER

2. FAULT LINE

4. FOCUS 1. FAULT

3. EPICENTER

WHAT IS AN EARTHQUAKE AND WHEN WILL IT OCCUR?

Earthquake is shaking of the ground cause by a release of an energy from beneath it.

Earthquake occurs when rocks along a fault suddenly move due to the release of energy from the ground as friction limits between rocks is reached.

2.

Earthquakes occur when rocks slip along faults.

Earthquake and Seismic Wave

• Seismic waves are waves that travel through the Earth carrying the energy released during earthquakes.

Types of Seismic WaveBody waves travel in all directions from the focus through the body of the Earth inner layers(core, mantle, crust).

Surface waves don’t travel through the Earth but instead they are constrained to travel along the surface of the Earth only from the epicenter(outer crust).

Primary WavesPrimary waves (compressional waves) are the fastest form of wave that can move through solids, liquids and some gases.

These waves cause rock particles to move back and forth in the same direction as the wave is traveling (push-pull).

Primary Waves

Secondary WavesSecondary waves (shear wave) are slower than the primary and travel through solids only.

Cause rock particles to move back and forth at right angles to the line of wave movement.

Secondary Waves

Types of Body Waves

Where do Primary and Secondary wave start to travel?

From the focus.

Rayleigh WavesRayleigh waves are causing the ground to shake in an elliptical motion.

It moves the ground up and down, and side-to-side in the same direction that the wave is moving.

Most of EQ shaking is due to this type of wave.

Rayleigh Waves

Love WavesLove waves are waves produce entirely horizontal motion.

It moves the ground side-to-side .

Love Waves

Types of Surface Waves

Where do Rayleigh and Love wave start to travel?

From the epicenter.

Which type of wave causes thousands of death and structural destruction – body or surface? Explain.

The surface waves because they are the ones that carries the released energy in the surface where infrastructures are built on.

Summary

• Seismic waves – are vibrations that travel through the Earth carrying the

energy released during earthquakes.

• Body waves – travel in all directions from the focus through the body

of the Earth inner layers(core, mantle, crust). – Types are primary and secondary waves.

• Surface waves – don’t travel through the Earth but instead they are

constrained to travel along the surface of the Earth only from the epicenter(crust).

– Types are Rayleigh and Love waves.

SUMMARY

ACTIVITY• Make a Pantomimed demonstration.• Demonstrate the movement of the each type of

seismic wave.• All members should be part of each chain type of

seismic wave.• Wave direction is to the right and left.• You have 5 minutes to practice your demonstration.• You may make your own moves which are still in

line with the exact movement of the waves.• YOUR TEACHER WILL BE THE ONE TO CHOOSE

WHAT TYPE OF WAVE YOU ARE GOING TO PRESENT FIRST AND SO ON.

ACTIVITY

YOU WILL BE GRADED ACCORDING TO THE FOLLOWING:Understanding of the concept 50Mastery 20Creativity 20Team Work 10

Example