1. Do Now Which type of boundary creates new lithosphere/oceanic crust?
Which type of boundary is associated with mountains and volcanoes?
This boundary neither creates nor destroys plates.
At which specific type of convergent boundary is lithosphere destroyed?
What was the main question that the theory of plate tectonics answered?
Ryan is visiting the mountains in Colorado. What type of tectonic plate boundary is Ryan near?

2. What happened in Japan? Tsunami hitting the coast:

3. The red dots are locations of Earthquakes
The red dots are locations of Earthquakes. Make an observation and an inference about this map.

4. San Francisco 1989
SF Earthquake 1989 (longer)

5. What is a focus?
The point beneath the Earth’s surface where rock under stress breaks to cause an earthquake.

6. The point on the surface directly above the focus.
What is an epicenter?
The point on the surface directly above the focus.

8. The farther the distance between the focus and the epicenter, the weaker the earthquake. Therefore, the closer the focus is to the surface, the stronger the earthquake.

9. Distance from Focus to Epicenter

11. Haiti Earthquake Read and annotate the short article
Answer the questions below

12. Quick Review
What instrument do scientists use to measure an earthquake?
What causes an earthquake?
Label the fault, epicenter, and focus in the picture to the right.
A =
B =
C = b a c

13. Seismic waves are the waves (vibrations) caused by earthquakes
What are seismic waves?
Seismic waves are the waves (vibrations) caused by earthquakes

14. During an earthquake, vibrations called seismic wave move out from the focus in all directions similar to the ripples created by a pebble in a pond.

16. Seismic waves carry the energy of an earthquake away from the focus, through the Earth’s interior, and across the surface.

18. What are the three types of seismic waves?
Primary waves
(P waves)
Secondary Waves
(S waves)
Surface waves (L waves)

19. Describe a P wave. Travel the fastest
Travel solids, liquids, and gases
Move through the Earth at different speeds, depending on the density
Called “push-pull” waves (compress and expand the ground like an accordion)

21. 21

22. Describe an S wave. Arrive at a given point after the P waves
Travel only through solids
Move through solids at different speeds depending on the density
Cause rock particles to move from side to side & up and down

24. 24

25. Describe a L wave. Slowest of the seismic waves
Move along the Earth’s surface like waves travel in the ocean
Cause most of the damage during an earthquake

27. When the P & S waves reach the surface, they move more slowly creating the most severe ground movements.

28. What do scientists use to detect and measure earthquakes?
Seismographs are used by scientist to detect, measure & record the vibrations of seismic waves.
What do scientists use to detect and measure earthquakes?
An earthquake’s magnitude is a
measurement of its strength based
on seismic waves and movement
along faults.

31. Seismic Wave Demo

32. EQ & Seismic Wave Foldable
Let’s Fold and Label together
The directions for the inside of the foldable is at your station

33. What are 3 rating scales used to measure an earthquake?

34. Mercalli scale –
This scale rates earthquakes by describing their effects on people, buildings, and the land surface in a given location.

40. Richter scale
This scale rates earthquakes according to the size of seismic waves as measured by the seismograph.

41. Moment Magnitude scale
This scale rates earthquakes by estimating the total energy they release. The moment magnitude scale can be used to measure earthquakes of all sizes, near or far!

42. How do scientists determine the location of an earthquake’s epicenter?

43. When an earthquake strikes, P waves are the first to arrive at a seismograph followed by the S waves.
The farther away the epicenter is, the greater the difference between the two arrival times.

45. This difference in time tells scientists how far the seismograph is from the epicenter. This information is then used to plot a circle on a map.

46. The circle shows the distance from one seismograph station to all points where the epicenter could be located.

47. .

48. To determine the exact location of the epicenter, at least THREE stations need to find their distance from the epicenter and draw a circle on a map

49. The single point where the 3 circles intersect is the location of the earthquake’s epicenter.