 List the names of the interior layers of the Earth beginning with the core.  But wait, we didn’t learn that…… where ever could we find such information?

 Using the copy of page 10 in the ESRT, count how many interior layers there are inside Earth and take a colored pencil for each layer.  Color each layer a different color.  With you partner, answer the questions about the layers.

 How is it possible for us to know all of this about the inside of Earth?

Interior Layers of the Earth:

 An earthquake is the vibration of Earth produced by rapid release of energy.  Focus is the point within Earth where the earthquake starts.  Epicenter is the location at the surface directly above the focus.

 Faults are fractures in Earth where movement has occurred.

 Earthquakes are caused when the strength of the rock is exceeded.  It suddenly breaks causing the vibrations of an earthquake.

These vibrations travel in the form of seismic waves.

 There are two kinds of seismic waves  Body waves travel through the Earth.  When body waves reach the surface of the Earth they are called surface waves. There are two types of body waves travel through Earth: 1.P waves 2.S waves

 P waves (compression) can travel at the fastest speed and can move through solid, liquid, and gas!  S waves (shear) travel slower and can only move through solids!

 Which interior layers of Earth can S waves move through? (Use your ESRT)  Why?

 A Tsunami is an underwater earthquake.  When there is a shift in the ground underwater, it displaces or moves the water.  The water waves travel trough the deep water.  When they approach shallow depths, the energy in the wave is conserved by increasing wave height.

 Let’s meet Patty and Sarah!

 A seismograph is an instrument used to detect and record seismic waves.  A seismogram is the actual recording on paper. How do we know that P waves (compression) travel faster than S waves (shear)?

-How do we know that P waves (compression) travel faster than S waves (shear)?

-Because they always show up first on a seismogram.

 According to the graph of Earthquake P-wave and S- wave Travel Time in the reference information, what is the approximate total distance traveled by an earthquake’s P-wave in its first 9 minutes?  2,600 km  5,600 km  7,600 km  12,100 km

Let’s have some fun with numbers!!!

 What can the difference in P wave and S wave travel time can tell us about an earthquake?  Let’s figure it out together……..  Turn to page 11 in your ESRT!

Earthquakes Seismograms at three stations

Earthquakes *Which Station is closer to the earthquakes epicenter? *What information did you use to figure that out?

 Station A: San Francisco, California P-Wave arrival 3:02:20S-Wave arrival 3:06:30 What is the time difference between P and S wave arrivals?

 Station B: Denver, Colorado P-Wave arrival 3:01:40S-Wave arrival 3:05:00 What is the time difference between P and S wave arrivals?

 Station C: Missoula, Montana P-Wave arrival 3:01:00S-Wave arrival 3:03:00 What is the time difference between P and S wave arrivals?

San Francisco: 4:10 Denver, Colorado: 3:20 Missoula, Montana: 2:00

Time to…. Surf the wave!

TAKE A PIECE OF PAPER, AND MARK OFF THE DIFFERENCE IN ARRIVAL TIME

MOVE THE PAPER UNTIL THE TWO TICK MARKS LINE UP WITH THE P AND S CURVES WHEN TICK MARKS LINE UP, GO STRAIGHT DOWN AND READ THE EPICENTER DISTANCE EPICENTER DISTANCE OF 2800 KM

San Francisco: 4:10 Denver, Colorado: 3:20 Missoula, Montana: 2:00 Try the other two on your own.

San Francisco: 4:10 2,800km Denver, Colorado: 3:20 2,000km Missoula, Montana: 2:00 1,100km

 The diagram shows data received at a seismic station following an earthquake.  The distance from this seismic station to the epicenter of the earthquake is approximately….. a.1,300 km b. 2,600 km c. 3,400 km d. 5,000 km

Let’s practice with Epicenter Info!

 So what does this distance we get from the ESRT tell us anyway?

San Francisco: 4:10 =2,800km 1,000 2,000 3,000 4,0005,000 Open your compass to the EXACT distance on the scale.

... 2,800km

San Francisco: 4:10 2,800km Denver, Colorado: 3:20 2,000km Missoula, Montana: 2:00 1,100km

... 2,800km 2,000km

San Francisco: 4:10 2,800km Denver, Colorado: 3:20 2,000km Missoula, Montana: 2:00 1,100km

... 2,800km 2,000km 1,100km

... 2,800km 2,000km 1,100km

Earthquakes

 We know that P and S waves are the body waves that travel through Earth.  Surface waves only travel along Earth’s surface.  We describe surface waves as either Love waves or Raleigh waves.  Check this out geo.mtu.edu/UPSeis/waves.html

 But wait, how do P and S waves behave?  Time to play with the slinky!!!  How can we get the slinky to behave like a P wave?  An S wave?  Recall the terms compressional and shear.

Team Challenge: Each class will be timed!! Make a human P wave in order to get “energy” to travel from one side of the room to the other! Then make a human S wave!!! Ready….Set…..Go

 Recall: When traveling through the same material P waves move faster than S waves.  Recall: S waves can only travel through solids while P waves travel through solids and liquids! -Waves refract (change direction) and speed up as density increases. -Since density increases with depth, the wave path looks something like this…….

 Shadow Zone (120 degrees, 143 degrees)  Richter Scale  Mercalli Scale