USING EARTHQUAKES TO STUDY THE EARTHS INTERIOR

1
LESSON 14

• USING EARTHQUAKES TO STUDY THE EARTHS INTERIOR

2
OBJECTIVES

• EXAMINE THE INTERIOR STRUCTURE OF SOME COMMON
  OBJECTS .
• DISCUSS HOW SCIENTISTS STUDY THE STRUCTURE OF THE
  EARTHS INTERIOR.
• RECOGNIZE THAT AN UNDERSTANDING OF THE MOTION OF
  EARTHQUAKE WAVES CAN HELP SCIENTISTS FORMULATE
  HYPOTHESES ABOUT THE EARTHS INTERIOR.

3

• USING COMPUTER IMAGES, IDENTIFY AND DESCRIBE THE
  LAYERS OF THE EARTH.
• PLOT THE LOCATIONS OF VOLCANOES AND COMPARE THESE
  LOCATIONS WITH THOSE OF EARTHQUAKES.

4
GLOSSARY

• CRUST THE OUTER LAYER OF THE EARTH THAT IS
  RIGID AND COMPOSED OF A WIDE VARIETY OF ROCKS.
• OCEANIC CRUST APPROXIMATELY 5-10 KM. THICK AND
  LIES BENEATH OCEAN WATERS.
• CONTINENTAL CRUST CONTAINS LANDMASSES AND
  RANGES FROM 15-70 KM.
• MANTLE LAYER BENEATH THE CRUST THAT EXTENDS
  FROM THE BASE OF THE A CRUST TO A DEPTH OF ABOUT
  2900 KM.

5

• OUTER CORE LAYER OF THE CORE THAT IS MADE OF
  MOLTEN IRON AND EXTENDS TO A DEPTH OF 5140 KM.
• INNER CORE LAYER BENEATH THE OUTER CORE THAT IS
  SOLID NICKEL AND IRON. THE CENTER IS 6378 KM.
  FROM THE EARTHS SURFACE.
• LITHOSPHERE - THE OUTERMOST LAYER OF EARTH WITH
  A TYPICAL THICKNESS OF 18-120 KM. REMAINS COOL
  AND RIGID.
• ASTHENOSPHERE THE LAYER BENEATH THE
  LITHOSPHERE. HOTTER AND MORE VISCOUS.

6
GETTING STARTED

• LOOK AT THE OBJECTS PRESENTED AT EACH TABLE (OR
  BY YOUR TEACHER). APPLE, HARD-BOILED EGG, PEANUT
  MM
• A. WHAT DO YOU THINK EACH ITEM LOOKS LIKE
  INSIDE?
• B. HOW COULD YOU FIND OUT ABOUT THE STRUCTURE OF
  EACH ITEM?

7

• NOW CUT OPEN EACH ITEM. IF POSSIBLE, CUT OPEN
  THE HARD-BOILED EGG WITH THE SHELL ON. COMPARE
  AND CONTRAST EACH OBJECT.
• A. HOW DO YOU THINK THE STRUCTURE OF THESE ITEMS
  RESEMBLES THE STRUCTURE OF THE EARTHS INTERIOR?
  
• THE EARTH ALSO HAS LAYERS.
• B. HOW DO YOU THINK SCIENTISTS STUDY AND LEARN
  ABOUT THE EARTHS INTERIOR?
• MODELS
• STUDYING EARTHQUAKE WAVE BEHAVIOR

8
INQUIRY 14.1- EXAMINING THE EARTHS INTERIOR

• THINK ABOUT IT
• HOW WOULD SCIENTISTS USE EARTHQUAKE WAVES TO
  DETERMINE WHETHER THE INTERIOR OF THE EARTH
  CONTAINS LAYERS OF SOLID, LIQUID, OR GAS?

9
OBSERVE AND RECORD

• WRITE WHAT HAPPENS WHEN A DROP OF WATER IS PLACED
  AT THE EDGE OF THIS TRAY.
• RECORD YOUR OBSERVATIONS
• NOW PREDICT WHAT WOULD HAPPEN TO A WAVE WHEN IF A
  CAN IS PLACED IN THE CENTER (CORE) OF THE WATER.
• LETS TEST OUR PREDICTIONS AND RECORD WHAT
  HAPPENS.

10
LOOK AT THE ILLUSTRATION OF THE EARTHS INTERIOR
ON PAGE 167.
11

• WHAT DO YOU THINK THE MOTION OF AN EARTHQUAKE
  WAVE CAN TELL US ABOUT THE EARTHS INTERIOR?
• EARTHQUAKE WAVES TRAVEL THROUGH SOME SUBSTANCES
  BUT NOT THROUGH OTHERS.
• WAVES TRAVEL AT DIFFERENT SPEEDS, DEPENDING ON
  THE PROPERTIES OF THE SUBSTANCE THROUGH WHICH
  THEY ARE MOVING.

12
CD-ROM SEGMENT 2 The Earths Interior

• IDENTIFY THE CHARACTERISTICS OF EACH LAYER
• AS DESCRIBED IN THE CD-ROM.
• INTERNAL COMPOSITION CRUST, MANTLE, CORE
• INTERNAL PHYSICAL PROPERTIES LITHOSPHERE AND
  ASTHENOSPHERE

13

• READ PG. 167, THE EARTHS INTERIOR, IN YOUR
  C.E. BOOKS.

14
ANSWER THESE QUESTIONS IN YOUR NOTEBOOKS

• A. WHY ARE THE IMAGES ON THE CD-ROM AND IN THE
  READING SELECTIO DRAWINGS RATHER THAN
  PHOTOGRAPHS?
• B. DESCRIBE EACH LAYER OF THE EARTH.

15
READ PGS. 168-169 USING WAVES TO EXPLORE THE
EARTHS INTERIOR IN YOUR C.E. BOOK.

• DESCRIBE HOW EARTHQUAKE WAVES HELP SCIENTISTS
  LEARN MORE ABOUT THE EARTHS INTERIOR.

16
HOMEWORK

• IN YOUR NOTEBOOKS.
• DRAW AND LABEL THE EARTHS INTERIOR. DIVIDE THE
  INTERIOR INTO
• CRUST, MANTLE, OUTER CORE, INNER CORE,
  LITHOSPHERE, ASTHENOSPHERE.
• COLOR EACH LAYER AND MAKE A KEY