Earthquakes: Part 2 CHAPTER 11 Learning Objectives: I can explain what causes an earthquake, what happens when one occurs, as well as the different types of hazards associated with them. 2) I can distinguish the four kinds of seismic waves: P-wave, S-waves, Rayleigh waves, and Love waves 3) I can match different earthquake focal mechanisms to the type of faulting, and I can relate them to different types of plate boundaries. Suggested tips to give students: All of these images were taken from the text unless otherwise credited. Look them up and read the captions … interesting and useful information that helps you relate to the subject matter

Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Learning Objective 3 I can match different earthquake focal mechanisms to the type of faulting, and I can relate them to different types of plate boundaries. Most earthquakes occur on plate boundaries, but some earthquakes occur within plates Suggested tips to give students: Notice the pattern? Plate margins are just difficult places to live. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Learning Objective 3 I can match different earthquake focal mechanisms to the type of faulting, and I can relate them to different types of plate boundaries. Divergent plate boundaries: Seismicity (i.e., earthquake activity) is typically shallow and low in magnitude. normal faulting ? ? strike-slip faulting Suggested tips to give students: Note that the shallow, intermediate, and deep earthquakes delineate the actual plate boundary. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

Learning Objective 3 I can match different earthquake focal mechanisms to the type of faulting, and I can relate them to different types of plate boundaries. Convergent plate boundaries: seismicity can extend to great depths along the subducting plate, i.e., along the Wadati-Benioff Zone. subduction Seismicity in back of the Tonga Trench reverse faulting is typical in the mantle ? Suggested tips to give students: Note that the shallow, intermediate, and deep earthquakes delineate the actual plate boundary. Tonga Trench Wadati-Bennioff Zone

Learning Objective 3 I can match different earthquake focal mechanisms to the type of faulting, and I can relate them to different types of plate boundaries. Transform plate boundaries: seismicity is frequent and can be hazardous in highly populated areas. ? Suggested tips to give students: Most earthquakes along transform plate boundaries tend to occur at shallow to moderate depths in the crust. strike-slip faulting is typical ?

Earthquakes: Part 3 CHAPTER 11 Learning Objectives: 1) I can identify the seismic characteristics of Earth’s major layers. 2) I can relate earthquake magnitude to the relative energy released and to the number of earthquakes that occur. 3) I can use seismographs to locate and earthquake and estimate its magnitude. Suggested tips to give students: All of these images were taken from the text unless otherwise credited. Look them up and read the captions … interesting and useful information that helps you relate to the subject matter

The seismic record around the world tells us the earth is layered. Learning Objective 2: I can identify the seismic characteristics of Earth’s major layers. The seismic record around the world tells us the earth is layered. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

S-wave shadow zones confirm the presence of a liquid outer-core Learning Objective 2: I can identify the seismic characteristics of Earth’s major layers and identify some structures found by seismic tomography P-wave and S-wave shadow zones confirm the presence of a liquid outer-core no core Slower seismic waves Faster seismic waves P waves Contraction forward and back pushing & pulling Faster seismic waves no S waves in liquid outer core S waves Slower seismic waves side-to-side shear

seismic velocity (km/s) Learning Objective 2: I can identify the seismic characteristics of Earth’s major layers and identify some structures found by seismic tomography Reflections and refractions confirm the presence of discontinuities in rock density inside the Earth 2) Lithosphere: defines the tectonic plate. 1) Core-mantle boundary (2900 km deep) 5 6 7 8 9 10 seismic velocity (km/s) S waves velocity = 0

(super dark chocolate) seismic velocity (km/s) Learning Objective 2: I can identify the seismic characteristics of Earth’s major layers and identify some structures found by seismic tomography Reflections and refractions confirm the presence of discontinuities in rock density inside the Earth 2) Lithosphere: defines the tectonic plate. P wave velocity (km/s) 6 7 8 9 mafic & intermediate rocks low seismic velocity higher seismic velocity ultramafic rocks (super dark chocolate) 1) Core-mantle boundary (2900 km deep) 5 6 7 8 9 10 seismic velocity (km/s) 3) Mohorovicic Discontinuity or “Moho”: base of the crust: ~ 7 km beneath oceanic basins ~ 20 to ~70 km beneath continents S waves velocity = 0

Earthquakes: Part 3 CHAPTER 11 Learning Objectives: 1) I can identify the seismic characteristics of Earth’s major layers. 2) I can relate earthquake magnitude to the relative energy released and to the number of earthquakes that occur. 3) I can use seismographs to locate and earthquake and estimate its magnitude. Suggested tips to give students: All of these images were taken from the text unless otherwise credited. Look them up and read the captions … interesting and useful information that helps you relate to the subject matter

Learning Objective 3: I can relate earthquake magnitude to the relative energy released and to the number of earthquakes that occur. Question 1: How many times more energy is released by a magnitude 7 earthquake compared to a magnitude 6 earthquake? 56,000,000 times more 1,800,000 times more 32 times more 2 times more

Learning Objective 3: I can relate earthquake magnitude to the relative energy released and to the number of earthquakes that occur. Richter Question 3: Which are more frequent, magnitude 5 earthquakes or magnitude 6 earthquakes? magnitude 5 earthquakes are more frequent magnitude 6 earthquakes are more frequent

Learning Objective 3: I can relate earthquake magnitude to the relative energy released and to the number of earthquakes that occur. Richter Question 4: How much more frequent are magnitude 5 earthquakes compared to magnitude 6? 10 times more 100 times more 1000 times more 100 times less

Earthquakes: Part 3 CHAPTER 11 Learning Objectives: 1) I can identify the seismic characteristics of Earth’s major layers. 2) I can relate earthquake intensity to the effects felt and relate earthquake magnitude to the relative energy released. 3) I can use seismographs to locate and earthquake and estimate its magnitude. Suggested tips to give students: All of these images were taken from the text unless otherwise credited. Look them up and read the captions … interesting and useful information that helps you relate to the subject matter

Learning Objective 4: I can use seismographs to locate and earthquake and estimate its magnitude.

Learning Objective 3: I can relate earthquake magnitude to the relative energy released and to the number of earthquakes that occur. The earthquake Intensity Scale (Modified Mercalli) measures effects on people and buildings.

Earthquake Prediction: We cannot predict WHEN the earth will break but we can estimate where hazards are more and less likely.

Seismologists use seismic tomography to image structures in Earth Learning Objective 2: I can identify the seismic characteristics of Earth’s major layers. Seismologists use seismic tomography to image structures in Earth Subducting Gorda and Juan de Fuca Plates Yellowstone mantle plume

(see http://www.youtube.com/watch?v=Hrto0nIP8nk) Learning Objective 2: I can identify the seismic characteristics of Earth’s major layers. Seismic tomography is used to image the Earth’s interior like a CT scan (see http://www.youtube.com/watch?v=Hrto0nIP8nk) Red = slow seismic waves, low density, hot Blue =fast seismic waves, high density, “cool”

Tomography images of the Hawaiian mantle plume Learning Objective 2: I can identify the seismic characteristics of Earth’s major layers. NW SE Tomography images of the Hawaiian mantle plume Red = slow seismic waves, low density, hot Green= normal mantle Blue =fast seismic waves, high density, “cool” Kilauea NW SE