What are earthquakes and volcanoes? Chapter 6 Lesson 2 SPI’s: Science 7.7.1, Reading 5.1.1, 5.1.2, 5.1.5, , , , , ,

In This Lesson We Will Learn: Why most earthquakes and volcanoes occur at plate boundaries.

Have you ever heard about a volcano or an earthquake? Let’s talk about it… Where was it? What were the details?

Why do we need to learn about Earthquakes and Volcanoes? Volcanic eruptions and earthquakes can be violent events. By learning more about them, we may be able to avoid some of the dangers they pose.

Think of it like this… When a fruit pie bakes in the oven, juices and steam seep up through cracks in the crust. That is similar to how a volcano forms. Wouldn’t you want to know when THAT was coming?

Do you think there is a pattern to the occurrence of volcanoes and earthquakes?

To find the answer, let’s do a class experiment. Turn to P. 213 in your text Using the earthquake and volcano list on P. 213, we will identify these locations on our classroom atlas. We will use two different colored sticky notes One color will represent volcanoes, and one color will represent earthquakes. Hint: If you are called on to locate one of these cities, look in the area of the Pacific Ocean.

Experiment continued Do you see a “ring” around the Pacific Ocean? Does anyone know what that ring is called?

The Ring of Fire!!!

Why is this area called, “The Ring of Fire”?

Answer Volcanoes and earthquakes are very common along the Ring of Fire.

Why are volcanoes and earthquakes more common around the Ring of Fire? Hint… it has something to do with the movement of Earth’s plates…

Answer Most volcanoes and earthquakes occur near plate boundaries; for example, around the edge of the Pacific Ocean.

Ring of Fire Let’s jump ahead to P. 220 in your text and read about the Ring of Fire.

Vocabulary Get out your Science journals... It’s time to “get smart”!!! Earthquake Epicenter Fault Focus Magma Seismic waves

Vocab. Cont… Earthquake: violent shaking of Earth’s crust as built–up energy is released

Vocab. Cont… Epicenter: point on Earth’s surface directly above the focus of an earthquake Turn to page 216 in your text. Look at the graphic titled, “Seismic Waves”. Notice the epicenter labeled on the second graphic.

Vocab. Cont… Fault: crack in Earth’s crust along which movement takes place The San Andreas fault extends almost the full length of the state of California!!

Vocab. Cont… Magma: melted rock below Earth’s surface; called lava at the surface Is this lava or magma?

Vocab. Cont… Seismic waves: waves of energy sent through Earth’s crust when plates move suddenly Turn to page 216 in your text. Look at the graphic titled, “Seismic Waves”. Notice the seismic waves labeled on the second graphic.

I need a volunteer, please We’ll take turns reading pages 214 and 215. Who would like to go first? (Remember, when we read, we pay attention to what we are reading, and we read with expression and enthusiasm!!!)

Let’s be detectives… Who can go back and find two words with the root – verge? Who can tell me what verge means?

Verge means… Verge comes from the Latin word vergere, which means “to turn”, or “to bend” The prefix con – means together The prefix di – means two Now, let’s be detectives and figure out (using our new clues) what converge and diverge mean.

Remember: In This Lesson We’re Learning: Why most earthquakes and volcanoes occur at plate boundaries.

Question What information does a seismograph record?

Answer The strength of seismic waves moving through Earth’s crust and along the surface. (you’re so smart!!!)

Question How is a diverging boundary fault created? (c’mon man, think!!!!)

Answer At diverging boundaries, stress builds up between blocks. Eventually, the rock breaks, and one block moves down a sloping crack. (Remember, “di” means two, and “verge” means “to turn” or “to bend”)

Let’s try another one… At what type of fault does force squeeze rock, causing it to break and causing the rock on one side of the fault to move up while the rock on the other side moves down? …you know this!!

Answer Fault at converging boundaries Way to go!!!!!!!

Let’s continue reading P. 216 I need a volunteer to begin reading the paragraph titled “Earthquakes” *While your classmate is reading, listen for the meanings of the words, “magnitude” and “intensity”. When you hear it, raise your hand!!!

Compare and Contrast It’s Science journal time… In your journal, compare and contrast how the measurements of an earthquake’s magnitude and intensity are alike and different. Refer to your text of you need help. Learning about earthquakes is so cool!!!

Let’s continue reading P. 217 This time; while your classmate is reading, I want you to figure out why surface waves cause great damage.

Answer Surface waves make the ground swell and roll.

Question Would an earthquake that measures 7.7 on the Richter scale cause blocks of rock to shift a lot or a little?

A lot!!! Remember… the higher the number, the greater the damage! You Rock!!!

Let’s Talk Volcanoes… Where does the word “volcano” come from? (You’re “gonna” love this…)

Answer The word volcano comes from the name of the ancient Roman god of fire, Vulcan. (Pretty cool, eh?)

I need a volunteer, please… We’ll take turns reading PP. 218 and 219. Remember, when you’re reading to the class, pay attention to what you are reading, and use expression. Be sure to follow along as your classmate reads because YOU could be the next one called on to read!!

In Your Science Journals Compare and Contrast: How are a crater and a chamber alike and how are they different? Classify: If you saw a volcano, what clues would tell you what type of volcano or volcanic cone it was?

Way To Go!!! Now you know why most earthquakes and volcanoes occur at plate boundaries!!!