Earthquakes are measured by 2 scales. One scale measures the DAMAGE an earthquake causes and the other measures the
MAGNITUDE or size of an earthquake created by the seismic waves. The two most popular scales are called the Richter Scale and the Mercalli Intensity Scale.
The first is called the
RICHTER SCALE . The
Richter Scale measures the size or MAGNITUDE of an earthquake. It measures the maximum amplitude of the “S” waves created by an earthquake.
Each step is 10 times the magnitude and releases
30% more energy.

Earthquakes are measured by 2 scales. One scale measures the DAMAGE an earthquake causes and the other measures the
MAGNITUDE or size of an earthquake created by the seismic waves. The two most popular scales are called the Richter Scale and the Mercalli Intensity Scale.
The other Scale is called the Mercalli Scale
The Mercalli Intensity Scale measures the DAMAGE done by an earthquake.
Why is this scale not as accurate as the Richter
Scale?

• Chino hills (30 miles from LA) 6.4 Ricther.

1.
Name the “description” the “earthquake effects” and the
“frequency” of a magnitude 7.3 earthquake.
2.
Name the “description” the “earthquake effects” and the
“frequency” of a magnitude 4.5 earthquake.
3. What would you expect to feel during a Mercalli scale rated Earthquake of a IV (4)?
4. What would you expect to feel during a Mercalli scale rated Earthquake of a X (10)?
5. Describe the motion of a raleigh wave.
6. Describe the motion of a love wave.
7. Put the following in order from fastest to slowest. Love wave, primary wave, secondary wave.
8.
Please have a ½ sheet of paper out for your 8.2 quiz.

1. Define Surface waves
2. Which waves are faster P waves or S waves (complete sentence!)
3. What are instruments that used to measure earthquake waves?
4. According to the book, P waves are also called
_________ waves.
5. Seismogram shows this type of wave(s) a) P waves b) S waves c) surface waves
6. Define S waves.
7. List the 2 categories of seismic waves.
d) All

LOCATIN’ THE SHAKIN’!!
Seismologists locate earthquakes by measuring the time between the P and S waves on a seismogram, produced by a seismoGRAPH.
After a seismograph "feels" an earthquake, scientists compare the time difference of these waves to figure out how far away the earthquake is.

EARTHQUAKES!
• How do we calculate the magnitude (richter scale) of an earthquake?
• Pieces of information needed:
– Time (seconds) between when the P waves and S waves arrived. Called
“LAG” time.
– Amplitude of the tallest S wave, measured in millimeters.
– ABILITY to read charts
C.O. – SWBAT understand the richter scale magnitude of Earthquakes and be able to locate Earthquakes using triangulation.
L.O. – SW practice how to read and calculate nomograms and triangulation.

1. How many seismographs do we need to locate the epicenter of an earthquake?
2. Describe how a convection oven is better than a regular oven.
3. What type of waves are P and
S waves? (not body/surface)
4. The map to the right shows the
Effects of an earthquake based off of the Mercalli scale. Describe the differences (damage) between the
4 zones shown.
5. What city was the closest to the epicenter?
6. Why are 9’s so far away from the epicenter?

LOCATIN’ THE SHAKIN’!!
• Time between P and S waves =
• Amplitude of the highest S wave =

LOCATIN’ THE SHAKIN’!!
• Lag time converted to distance in km

LOCATIN’ THE SHAKIN’!!
• Distance and amplitude gives us MAGNITUDE.

LOCATIN’ THE SHAKIN’!!
Because we know the relative speeds of earthquake waves, we can measure the time between the P and S waves to understand how far away the
Earthquake occurred.

LOCATIN’ THE SHAKIN’!!
We then can measure the AMPLITUDE of the S wave to then calculate the magnitude of an earthquake wave.

LOCATIN’ THE SHAKIN’!!
It takes at least three seismographs to locate an earthquake’s epicenter.

One seismograph can only tell how far away it is from that seismograph.
By measuring the S-P wave times at 3 or more stations, these circles can be drawn around each station (seismograph) and where they meet indicates the earthquake location.

Today you will be calculating distance and the radius of circles of 3 overlapping seismograph stations.
READ THE DIRECTIONS!
USE cm DO NOT USE cm
ON COMPASS!!
Color each set of circles the same color so you don’t get confused. I.E. EQ1 = blue.
FOLLOW THE
DIRECTIONS!
Hints on drawing circles.

#’s used
Easy to figure out
Energy Released per whole # on the scale (ex: from a 1 -2)
Energy released from a Mag. 3 to 4
Energy released from a Mag. 3 to 5
Energy released from a Mag. 6 to 7
Energy released from a Mag. 6 to 9
Richter Scale
1-10
YES
Moment Magnitude Scale
1-10
NO
Each step 10x greater Each step is 32x greater
4 is 10x greater than 3 4 is 32x greater than 3
5 is 100x greater than 3 5 is 1024x greater than 3
7 is 10x greater than 6 7 is 32x greater than 6
9 is 1000x greater than 6 9 is 32,768x greater than 6

1. Use the following terms and place them in outline format.
Choose the order you feel is the most logical. Use your notes and your group to discuss the best flowing outline.
You may need to write your own descriptions.
P waves
Love waves
1-10
I-IIV
Richter scale
Surface waves x10 mercalli scale
Transverse waves
Damage
Types of earthquake waves
Raleigh waves
S waves
Body waves
Longitudinal waves
Magnitude
Example of outline format:
1. Main idea or theme
A. Sub-idea or theme a) Another sub idea or theme
B. Second Sub idea a) Etc..
b) Etc…
2. Another main idea or theme
A. Etc..
B.
Etc… a) Etc…

Amplitude
P waves
S waves

Amp
1. Eureka, CA;
0 s
S-wave arrival = ____________
49 s
285 mm
P S

Now do the other 2 on your own
Elko, NV
Las Vegas, NV

Richter Magnitude =
_________________

C.O. – Students will explore earthquake effects on the crust of the earth and the rock layers associated with it.
L.O. – Students will practice reading nonograms, seismograms and use them to compare the effects of earthquakes.

Please collect one of the half sheets from the front. These will need to be
ATTACHED to your notebook (taped or glued in) by Monday. NO I do not have stuff you can borrow right now to do it. Use the 2 graphs to answer the following questions. You will be using these graphs many times so if you write on them, write lightly so you can erase and use over and over. These are for reference.
1. How far away is an EQ with an SP lag time of 55 seconds?
2. If an EQ happened 400 kilometers away, how long should I expect the lag time to be?
3. If an earthquake was 100 kilometers away and had an amplitude of
20mm, what would its estimated magnitude be?
4. If a seismogram had an S wave amplitude of 100mm and was a magnitude 5.0, estimate about how far it was away from that seismograph station.
5. An earthquake lag time was about 60 seconds. The S waves recorded had an amplitude of 5mm. What was the magnitude of that
Earthquake?
6. A seismogram had an amplitude of 200mm and an estimated magnitude of 7.0. About how far away was that Earthquake and estimate about how long lag time between P and S waves would be.

500 600 700

Now that you are an expert on finding the magnitude and epicenter of an earthquake, work to calculate both for our second earthquake.
This work and the lab questions will be due at the beginning of class tomorrow.

1. Describe a reason why it is very difficult to predict earthquakes.
2. Name the 2 types of earthquake waves
3. Which are body waves?
4. Which waves are Surface waves?
5. If a seismogram had an S wave amplitude of 80mm and was a magnitude 5.0, estimate about how far it was away from that seismograph station.
6. An earthquake lag time was about 50 seconds. The S waves recorded had an amplitude of 5mm. What was the magnitude of that Earthquake?
7. A seismogram had an amplitude of 100mm and an estimated magnitude of 6.0. About how far away was that Earthquake and estimate about how long lag time between P and S waves would be.

1. Based on the map and your mercalli scale, what is the highest level of destruction that happened here?
2. Use the Mercalli scale and the map to describe what
3 other cities felt.
3. What is the magnitude of this earthquake?
4. When did this earthquake occur?
5. Using your S-P chart and your nomogram, figure out the magnitude of an
Earthquake that was 60s away from a seismograph and had an amplitude of
100mm.

• Write this down…
• EQ location paper due tomorrow!
• QUIZ on how to read an S-P lag time chart, and an earthquake nomogram chart to figure out distance, magnitude and amplitude of an earthquake.
• Students should also know how to triangulate earthquakes.
C.O. – Students will understand how to read an S-P lag chart, an earthquake nomogram to calculate earthquake characteristics.
L.O. – Students will practice reading nomograms and S-P lag chart and use a compass to triangulate epicenters.

1. How far away is an earthquake if it took 35 seconds to get there?
2. If I have a lag time of 40 seconds, how far away did the earthquake occur.
3. How many seismographs do I need to find the epicenter of the earthquake?
4. How far is an earthquake away if it was 5.1 on the richter scale and had an amplitude of 100mm?
5. An earthquake had a magnitude of 7.0 and an amplitude of 500. How far away was the earthquake?
6. An earthquake occurred 200 km away with a magnitude of 5.9, what was its amplitude?
7. An earthquake occurred 60 km away and had an amplitude of 200 mm, what was its magnitude?

• Please have only a pen and or a pencil on your desk. Everything else off. You will need either your ID card or a ruler, or something you can use to draw straight lines.

• Words: continental drift, pangaea, Mesosaurus,
• Questions: 1-5
• If you are not finished with your Earthquake paper, you can finish that now but it is due today.
• If you are finished, your classwork for today is
9.1

Draw and
Describe the
Layers of the earth.

• The earth is made up of many layers. Just like an Egg.
• An egg has many layers

Crust
THICK JELLY
Hot
HEAT!
HEAT!
HEAT!
LIQUID
SOLID
Responsible of
MAGNETIC FIELD
HEAT!
Cold
Convection
Currents

• You will be having a quiz on the following words tomorrow.
• Please make the following words into flashcards so you can study them.
• DO NOT GET THEM FROM THE BACK OF
THE BOOK. The chapter and section of the book are listed next to the word, where you can find them.

• Crust (8.4)
• Mantle (8.4)
• Lithosphere (8.4)
• Asthenosphere (8.4)
• Moho (8.4)
• Pangaea (9.1)
• Mesosaurus (9.1)
• Continental drift (9.1)

Describe, in your own words, what plate tectonics is all about.
C.O. – Students will understand how the interior of the earth result in movement of tectonic plates.
L.O. – Students will practice read and discuss and take notes on the layers and tectonic plates

CAUSE – mantle convection EFFECT – moving plates