EXTRA CREDIT OPPORTUNITY! 1.Attend the musical this weekend. 2.Get the program signed by a cast member. 3.Bring it to class next week. 4.Earn 10 EXTRA CREDIT POINTS!

Thursday, May 6 th Agenda  Collect homework: “High Up in the Himalayas” worksheet  Quiz over section 19.1  Begin Section 19.2: Earthquakes and Volcanoes  Movie: “Earthquakes: Our Restless Planet”  Homework: “Plinian Eruptions” Worksheet We will finish section 19.2 next time…

Section 19.1: Earth’s Interior and Plate Tectonics Walk/Talk Quiz  Answer only the question that corresponds with your birthday month.  Once everyone has answered their 1 question, get up, walk and talk with your classmates to complete the rest of the quiz.  Don‘t just copy their answer, read the question, answer it yourself and see if you agree.  If you don’t, discuss it and try to come up with the correct answer together. Good Luck!

What are Earthquakes?  Earthquakes occur at plate boundaries.  Earthquakes are vibrations resulting from rocks sliding past each other at a fault  Seismic waves are waves of energy released during in earthquake  Focus the area along a fault at which the first motion of an earthquake occurs  Epicenter the point on Earth’s surface directly above an earthquake’s focus

What are Earthquakes? continued  Energy from earthquakes is transferred by waves.  Earthquakes generate three types of waves:  Longitudinal waves  Transverse waves  Surface waves  Longitudinal waves travel by compressing and stretching crust, also called primary waves (P waves)  Transverse waves travel in an up and downward movement, also called secondary waves (S waves)  Surface waves seismic waves that can move only through solids, move in a rolling circular motion

What are Earthquakes? continued  Waves move through Earth and along its surface.  Both P waves and S waves spread out from the focus in all directions through the earth.  Surface waves move only on Earth ’ s surface.

Measuring Earthquakes  Seismologists detect and measure earthquakes.  Seismology the study of earthquakes including their origin, propagation, energy, and prediction  Seismologists use sensitive equipment called seismographs to record data about earthquakes.

Measuring Earthquakes, continued  Three seismograph stations are necessary to locate the epicenter of an earthquake.  There are more than 1000 seismograph stations across the world.  Because P waves travel faster, the difference between the arrival of P waves and the arrival of S waves allows scientists to calculate how far away the focus is.

Measuring Earthquakes, continued  Geologists use seismographs to investigate Earth ’ s interior.  The way P and S waves travel through Earth ’ s interior help scientists make a model of Earth with layers of different densities.

Measuring Earthquakes, continued  The Richter scale is a measure of the magnitude of earthquakes.  Richter scale a scale that expresses the magnitude of an earthquake  The intensity of an earthquake is measured by the modified Mercalli scale. Intensity depends on many factors.  Earthquakes that occur deeper below the Earth ’ s surface will not be as intense at the surface.  The hardness of the rock above and around an earthquake affects the intensity.

Measuring Earthquakes, continued  Scientists are trying to predict earthquakes.  Scientists are trying to measure changes in Earth ’ s crust that might signal an earthquake.  The ability to predict an earthquake could save thousands of lives in the future.

Movie: “Earthquakes: Our Restless Planet”  Homework: – “Plinian Eruptions” Worksheet Have a GREAT weekend!!