1. Do Now: Answer the question below on the back of your exit slip 1
Do Now: Answer the question below on the back of your exit slip 1. Which statement best describes the continental and oceanic crusts? A) The continental crust is thicker and less dense than the oceanic crust. B) The continental crust is thinner and more dense than the oceanic crust. C) The continental crust is thinner and less dense than the oceanic crust. D) The continental crust is thicker and more dense than the oceanic crust.

2. What’s an “earthquake” is and what causes them?
Earthquake: a sudden movement of the earth caused when the crustal plates move.
What’s an “earthquake” is and what causes them?
LO:STUDENTS WILL BE ABLE TO EXPLAIN WHAT CAUSES EARTHQUAKES.

3. The scientific term for an earthquake is a seismic disturbance “seismos” means “shaking ground” in Greek.

4. seismologists: scientists who study earthquakes.

5. How do earthquakes occur?
Earthquakes are the shaking of Earth’s crust caused by the movement of rocks in the lithosphere.
Where Earthquakes Occur

6. Where do earthquakes occur?
POP QUIZ
Where do earthquakes occur?
Earthquakes usually occur at plate boundaries where there are major fault lines. However there are minor faults, or cracks in the crust all over the Earth.

7. FAULTS : weak areas or “cracks” in earth’s crust.
What is a fault?
A fault is a break, or fracture, in a rock along which motion of the rock has occurred. When the stress on the crust is greater than it can resist, the crust shifts and breaks which causes a sudden release of energy.
FAULTS : weak areas or “cracks” in earth’s crust.

8. If this egg was the earth, what do you think the faults would be?
If the Earth were an egg, the cracks in the egg would be the faults!
If this egg was the earth, what do you think the faults would be?

10. Earthquakes happen when there is movement along the faults lines where the crustal plates meet.

11. Every earthquake has a focus and an epicenter.

12. When an earthquake occurs, seismologists always try to locate the quake’s epicenter.
EPICENTER:THE PLACE ON EARTH’S SURFACE DIRECTLY ABOVE THE FOCUS.
THE FOCUS:THE PLACE UNDERGROUND WHERE THE EARTHQUAKE originated. The deeper the focus (focal depth) the more powerful the earth quake will be

13. How are earthquakes recorded?
Earthquakes are recorded by instruments called seismographs. The recording they make is called a seismogram. The seismogram records the waves of energy that are given off by an earthquake.

14. Seismograph
Seismogram

15. Seismograph in Action!

16. Earthquakes are measured using: the Mercalli scale & the Richter scale

17. The Mercalli Scale:
measures how intense an earthquake was based on eyewitness observation
After an earthquake, people report how bad they felt the quake was at their location.

18. Because it is based on personal observation, people may disagree about the intensity of the quake.
Especially at a distance from the quake.

19. In 1985, California alone had 17,000 earthquakes!
MILLIONS of earthquakes occur each year! most are too weak to feel. Do you think this scale is accurate?
The Mercalli Scale is considered to be subjective.
In 1985, California alone had 17,000 earthquakes!

20. The Richter Scale measures the magnitude (strength) of the vibrations.
On a scale 0 to 9.

21. THE RICHTER SCALE IS A LOGARITHMIC SCALE (X10)
Each magnitude is 10 times stronger than than the magnitude below it.
A “2” on the Richter Scale is 10 times stronger than a “1”.
A “3” is 10 times stronger than a “2”. Which means that a “3” is 100 times stronger than a “1”.

22. The strength of RICHTER SCALE magnitudes:
0: 600 grams of dynamite. You can blow up a tree.
1: 20kg. Of TNT.
2: 600kg of TNT.
3: 20,000kg. You can blow up a mine.
4: 60,000kg. Of TNT A small atom bomb.
5: 20 million kg of TNT a “standard” nuclear atom
6: 600 million kg of TNT. A small H bomb. 7: 20 billion kg of TNT. Enough to heat NYC for a year. 8: 600 billion kg. enough to heat NYC for 30 years. 9: 20 trillion kg. the energy of all of the coal & oil produced by the Earth for 5 years!

23. Do Now (4 minutes)
Take out your Notes, Earth Science Reference table and piece of paper (if you do not have one there is some in the back between the book shelf and printer)
Open your ESRT to page 11 and Answer this question on a piece of paper (write down the question):
What unit is on the X-axis and Y-axis of that graph? On the Y-axis what is it going up by (hint: 60 sec=1min)? On the X-axis what is it going up by(hint: 10^3 means you add three “0” to the end of the number. Ex. “1” becomes 1,000)?

24. There are three kind of waves given off by an Earth Quake
P-waves (Primary Waves)
S-waves (Secondary or Shear Waves)
L-waves (Surface waves)

25. P waves (Primary Waves (Primary waves) are the fastest traveling waves
are always detected first because they arrive first after an earthquake happens.
P waves can pass through both solids and liquids
As they move through crust, they push and pull with compression.

26. S waves (Shear Waves) always arrive second after an earthquake.
(Secondary waves) travel slower than p waves.
always arrive second after an earthquake.
only pass through solids
Move side to side.

27. L waves (Surface Waves)
The last waves to come
They are long period waves. also called Rayleigh and Love waves. And surface waves (because they travel on the surface)
They Elevate (lift) the crust as they ripple surface causing the most damage.
Whenever you see earthquake damage, it was caused by the L waves.

28. seismologists use the P-wave & S-wave data on seismograms:
Locate distance from the epicenter of a quake.
The P-wave & S-wave travel times.
The difference in arrival times.
Origin time of the earthquake.

29. There are some key words we must know to figure out when an earthquake started, will arrive or where it started!

30. Travel Time
Time-the amount of time a P-wave or S-wave to travels from the epicenter (the place where the quake started).
EX: Mr. V can run a mile in 7 minutes.
If Mr. V ran a mile race, how long did it take him?
7 minutes!

31. Arrival Time
Arrival Time
Arrival Time- the time the P-waves or S- waves arrived at the seismic station
EX: Mr. V can run a mile in 7 minutes.
If Mr. V ran a mile race at 7:00, at what time would he arrive the finish line?
Mr. V can run a mile in 7 minutes, so his arrival time would be 7:07 (7:00+:07=7:07)

32. Origin Time-The time the earthquake started.
EX: Mr. V ARRIVED at school 7:20.
Mr. V says it took 20 minutes to get there
What is Mr. V’s Origin Time from when he left ? 7:20-:20= 7:00

33. Difference in arrival time
The best way to describe this is by using your reference table
When they ask for difference in arrival time YOU MUST have a scrap piece
First find the difference between the P and S wave time
Then take your scrap piece of paper and line it up with the the line on the left side of your page 10 chart
Mark off the time you got and the 0 mark
Bring the scrap paper up on the two lines (p and s wave) until the two marks you made match up with the two lines (p and swave).
Go down and it will tell you the distance