Finding the epicenter worksheet - Earthquakes Earthquakes and ... - Free Printable

Let’s go step by step to fill in the graphic organizer and answer the questions.

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Step 1: Understand what seismic waves are

Seismic waves are energy waves that travel through Earth after an earthquake. There are three main types:

- P-waves (Primary waves) – These are the fastest and arrive first. They can move through solids, liquids, and gases.
- S-waves (Secondary waves) – Slower than P-waves. They only move through solids.
- Surface waves – Slowest but cause the most damage. They travel along Earth’s surface.

These are usually listed in order of arrival at a seismograph station: P-wave → S-wave → Surface wave.

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Step 2: Fill in the “Main Idea” graphic organizer

The chart says:
> Seismic waves carry the energy of an earthquake.

Then it has three boxes labeled “Detail” under columns a, b, c.

We’ll list the three types of seismic waves as details:

a. P-waves (Primary waves) – First to arrive; compressional waves that move through all materials.

b. S-waves (Secondary waves) – Second to arrive; shear waves that only move through solids.

c. Surface waves – Last to arrive; roll along the surface and cause the most shaking and damage.

*(Note: Some textbooks may list surface waves as two types — Love and Rayleigh — but for this level, grouping them as “surface waves” is fine.)*

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Step 3: Answer the Introduction questions

1. The point at which a rock under stress breaks and triggers an earthquake is called the ______.

→ This is the focus (also called hypocenter). It’s where the earthquake starts underground.

2. The point on the surface directly above the focus is the ______.

→ This is the epicenter.

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Step 4: Answer “Types of Seismic Waves” question

3. What are seismic waves?

→ Seismic waves are vibrations or energy waves that travel through Earth’s layers when an earthquake happens. They carry the energy released during the quake.

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Now let’s write the final answers clearly.

Final Answer:

Graphic Organizer Details:
a. P-waves (Primary waves) – Fastest, arrive first, move through solids, liquids, and gases.
b. S-waves (Secondary waves) – Slower than P-waves, arrive second, only move through solids.
c. Surface waves – Slowest, arrive last, travel along Earth’s surface, cause the most damage.

Introduction Answers:
1. focus
2. epicenter

Types of Seismic Waves Answer:
3. Seismic waves are energy waves that travel through Earth when an earthquake occurs.