Categories
Middle School MS Summer Science SCIENCE

Earthquakes

image_pdfDownload
Bookmark(0)

Page 2 Page 4




This book developed by ©Academy Global Learning 2020
All rights reserved under ©Academy Global Learning 2020. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyright owner.

Designed By:
Christian Alas
Created and illustrated By:
Angelo Romero and Camilo Sanabria

Earthquakes

An earthquake is the sudden shaking of the ground that happens when masses of rock under the earth’s surface shift or change positions. Earthquakes happen as a result of seismic waves created by energy that is suddenly released in the Earth’s crust. The magnitude or strength of an earthquake is measured by an instrument called a seismograph.

There is a scale called the Richter Scale that was set by scientists that determines the strength of earthquakes. A seismologist is a scientist who studies earthquakes. The focus of an earthquake is the point where the seismic waves begin. The epicenter of an earthquake is the point on the earth’s surface that is directly above the focus.

– 2 –

– 3 –

The strongest waves caused by the earthquake are called the surface waves. Primary waves of an earthquake are the seismic waves from the focus that are compressional. Secondary waves are seismic waves from the focus that are perpendicular to the motion.

The fracture in the earth caused by earthquakes is a fault. The San Andreas Fault in California is about 800 miles long. A normal fault is when the rock above a fault moves downward. A reverse fault is when the rock above the fault moves upward.

– 4 –


– 5 –

READING QUESTIONS

1. What is the writer’s main idea?

______________________________________
______________________________________
______________________________________

2. What example supports the writer’s main idea?

______________________________________
______________________________________
______________________________________

– 6 –

3. How does the example help the writer’s argument?

______________________________________
______________________________________
______________________________________

4. What do you think about the story?

______________________________________
______________________________________
______________________________________

– 7 –