By: Serena, Tamkina, and Olivia

Q2 2011

What is an Earthquake??

• Earthquakes are defined as movements of the ground that are caused be a sudden release of energy when rocks along a fault move.

Anatomy of an Earthquake

• The focus of an earthquake is the location within Earth along a fault at which the first motion of an earthquake occurs.

• The point on Earth’s surface directly above the focus is called the epicenter.

Seismic Waves

There are two main types of seismic waves:1. Body Waves

-P Waves (primary waves/compression waves)

-S Waves (secondary waves/shear waves)

2. Surface Waves-Love Waves

-Rayleigh Waves

Shadow Zones

• Shadow zones are locations on Earth’s surface where no body waves from a particular earthquake can be detected.

Earthquakes and Plate Tectonics

• Tectonic plates cause earthquakes by either diverging or converging at plate boundaries and tectonic environments. Some of these include:– Convergent Oceanic Environments– Divergent Oceanic Environments– Continental Environments

Recording and locating Earthquakes

• Vibrations in Earth’s surface can be recorded and detected using an instrument called at Seismograph.

• The tracing of the recorded earthquake’s motion is called a Seismogram.

• To determine where the epicenter of the earthquake was, scientists can analyze the arrival times of S and P Waves.

Earthquake Measurement

• Magnitude is the measure of the strength of an earthquake.

• Intensity is the amount of damage caused by an earthquake.

Tsunamis• A tsunami is a giant ocean wave that

forms after a volcanic eruption, submarine earthquake, or landslide.

AN EARTHQUAKE IS COMING!!

What should we do???

Before the earthquake

• Have a supply of:– Canned food– Bottled water– Flashlights– Batteries– Portable radio

• Discuss safety plans with your family

During the earthquake

• Stay Calm

• Move to a safe position– Indoors: stand in doorway

or under a table– Outdoors/in a car: move

away from tall buildings, tunnels, power lines, bridges

– Remain in the car until the tremors stop

After the earthquake

• Check for fire and other hazards

• Be cautious

• Wear shoes to avoid stepping on broken glass etc.

• Avoid objects touched by downed wires

Fun facts!!!!• The largest recorded earthquake in the world was a

magnitude 9.5 (Mw) in Chile on May 22, 1960.• Approximately 35 earthquakes occur in the US alone in one

year• Earthquakes typically last for about 60 seconds.• Each year the southern California area has about 10,000

earthquakes• Major earthquakes (magnitude 8 and greater) occur on

average of one per year. However, there are more than 1 million very small (magnitude 2.9 or smaller) earthquakes a year.

• Florida and North Dakota have the fewest earthquakes of any state.

• Alaska and California have the most earthquakes of any state.

Practice Questions!1. The _____ of an earthquake is the location within

Earth along a fault at which the first motion of an earthquake occurs.

A) Hotspot B) Focus C) Epicenter D) Body Wave

2. The two main types of seismic waves are:

A) Body & Structure B) Surface Waves & P-Waves

C) Body Waves & surface Waves D) Love & Rayleigh

3. Shadow zones are places where waves:

A) Don’t reach the surface B) Reach the surface very strong

4. A Seismogram is recorded by a:

A) Earthquakeomometer B) Seismogram C) Seismograph

Practice questions!5. Where is the epicenter?

A) Above the fault B) Above the focus

C) Below the fault D) Below the focus

6. What should you do during an earthquake?

A) SCREAM B) Go near a tall structure

C) Get in a doorway D) Stay near a powerline

7. What should you do when you are in a car during an earthquake?

A) Drive under a bridge B) Run out of the car

C) Move away from tall structures D) Pee

Practice questions!

8. What is a tsunami?

A) A giant wave caused by the moon

B) A tropical Hawaiian drink

C) A wave caused by a submarine earthquake, landslide, or volcanic eruption

D) A type of fish

9. Which item is NOT listed on the earthquake preparedness list?

A) Bottled Water B) Sunglasses C) Radio D) Food

10. A P-wave can also be called a ____ wave.

A) Shear B) Rayleigh C) Love D) Compression

Practice questions!11. What State, along with California, has the most

earthquakes in the US?A) Alaska B) New York C) Texas12. How long do earthquakes typically last?A)3 hours B)30 Seconds C)60 Seconds D)Forever13. What state, along with North Dakota, has the fewest

amount of earthquakes in the US?A) Washington B) Florida C) New Jersey14.After an earthquake, what should you wear?A) Gas Mask B) Gloves C) Shower Cap D) Shoes15. What should you discuss with your family prior to

an earthquake?A) Safety plan B) Math C) The meaning of life

Answers!!!!!1. C

2. B

3. A

4. C

5. B

6. C

7. C 13.B

8. C 14. D

9. B 15. A

10.D

11.A

12.C