2/11/2016discuss the elastic rebound theory California Science Content Standards Covered: ► Plate tectonics operating over geologic time has changed the

05/03/23 discuss the elastic rebound theory

California Science Content California Science Content Standards Covered:Standards Covered:

►Plate tectonics operating over Plate tectonics operating over geologic time has changed the geologic time has changed the patterns of land, sea, and patterns of land, sea, and mountains on Earth's surface. As mountains on Earth's surface. As the basis for understanding this the basis for understanding this concept:concept:

►3D: Students 3D: Students knowknow why and how why and how earthquakes occur and the scales earthquakes occur and the scales used to measure their intensities & used to measure their intensities & magnitudemagnitude

Terms Chapter 6 Terms Chapter 6 Define and write sentences or draw Define and write sentences or draw

picturespictures 1.1. EarthquakesEarthquakes2.2. Elastic rebound Elastic rebound

theorytheory3.3. AftershocksAftershocks4.4. FocusFocus5.5. EpicenterEpicenter6.6. Pacific ring of firePacific ring of fire7.7. Fault zonesFault zones8.8. SeismographSeismograph

9.9. P wavesP waves10.10. S wavesS waves11.11. Surface wavesSurface waves12.12. MagnitudeMagnitude13.13. MicroquakesMicroquakes14.14. Mercalli scaleMercalli scale15.15. IntensityIntensity16.16. TsunamiTsunami17.17. Seismic gapsSeismic gaps



Chapter 6 IntroductionChapter 6 Introduction►Ring of Fire►Earthquakes Earthquakes 1 & & 2

05/03/2305/03/23 discuss the elastic rebound theorydiscuss the elastic rebound theory

EarthquakesEarthquakes

Chapter 6Chapter 63D: Students 3D: Students knowknow why and how earthquakes occur and the scales used to why and how earthquakes occur and the scales used to

measure their intensities & magnitudemeasure their intensities & magnitudeElastic Rebound TheoryElastic Rebound Theory

Anatomy of a QuakeAnatomy of a QuakeEpicenter, focus, seismic wavesEpicenter, focus, seismic waves

Fore, primary, aftershockFore, primary, aftershockShallow, intermediate & deep focusShallow, intermediate & deep focus


Lecture 6.1Lecture 6.1Discuss elastic rebound theoryDiscuss elastic rebound theory

► Elastic Rebound TheoryElastic Rebound Theory When a When a STRESSSTRESS is applied, the road changes from its is applied, the road changes from its

original form – original form – ELASTIC DEFORMATIONELASTIC DEFORMATION When the RUPTURE relieves the STRESS, the ground under When the RUPTURE relieves the STRESS, the ground under

the road the road REBOUNDSREBOUNDS and returns to its original condition and returns to its original condition When the RUPTURE occurs, we feel the When the RUPTURE occurs, we feel the EARTHQUAKEEARTHQUAKE


Lecture 6.1Lecture 6.1Discuss elastic rebound theoryDiscuss elastic rebound theory


Explain why earthquakes generally Explain why earthquakes generally occur at plate boundariesoccur at plate boundaries

►Slippage first occurs at the Slippage first occurs at the FOCUSFOCUS►The place on the The place on the SURFACESURFACE of the Earth of the Earth

under the focus is the under the focus is the EPICENTEREPICENTER



►90% of earthquakes have a SHALLOW 90% of earthquakes have a SHALLOW focusfocus

► Intermediate and deep focus Intermediate and deep focus earthquakes (10%) occur 70 Km and earthquakes (10%) occur 70 Km and DEEPER DEEPER



►How does the depth of earthquakes How does the depth of earthquakes explain the type of a boundary?explain the type of a boundary?



►3 Major Earthquake Zones3 Major Earthquake Zones Mid Ocean Ridges – mainly divergentMid Ocean Ridges – mainly divergent Eurasian-Melanisian Belt – mainly convergentEurasian-Melanisian Belt – mainly convergent Ring of Fire – mainly convergentRing of Fire – mainly convergent

►Each dot represents an Each dot represents an EARTHQUAKE ZONEEARTHQUAKE ZONE


End Lecture 6.1End Lecture 6.1


Chapter 6 Section 2 Chapter 6 Section 2 ObjectivesObjectives

1.1. We will be able to compare the three We will be able to compare the three types of seismic waves.types of seismic waves.

2.2. We will discuss the method scientist We will discuss the method scientist use to pinpoint an earthquake.use to pinpoint an earthquake.

3.3. We will discuss the method most We will discuss the method most commonly used to measure the commonly used to measure the magnitude of earthquakes.magnitude of earthquakes.


Recording EarthquakesRecording EarthquakesLecture 6.2Lecture 6.2

► Seismic waves are Seismic waves are recorded on a recorded on a seismographseismograph

► 3 Major forms of 3 Major forms of waves recorded by waves recorded by seismographseismograph P WavesP Waves S WavesS Waves Surface WavesSurface Waves

http://www.sciencecourseware.com/eec/Earthquake/intro_imgs/index.php?imagename=alaska64

http://www.sciencecourseware.com/eec/Earthquake/intro_imgs/index.php?imagename=alaska2

http://www.sciencecourseware.com/eec/Earthquake/intro_imgs/index.php?imagename=sf3


P WavesP Waves► aka Primary Wavesaka Primary Waves► Travel the fastestTravel the fastest► Same direction as particle motionSame direction as particle motion► Travel Travel FASTERFASTER through through DENSERDENSER material material► Move through solids, gases and liquidsMove through solids, gases and liquids


S WavesS Waves► aka secondary or shear wavesaka secondary or shear waves►SLOWER than P WavesSLOWER than P Waves►Travel at RIGHT Angles to particles in Travel at RIGHT Angles to particles in

motionmotion►CANNOT pass through liquid or gasesCANNOT pass through liquid or gases


How to find the epicenterHow to find the epicenter►Method: Method: TRIANGULATIONTRIANGULATION►Must have three (3) seismographsMust have three (3) seismographs►Calculate the difference in P wave Calculate the difference in P wave

travel from all three travel from all three



Triangulation – Where is the epicenter Triangulation – Where is the epicenter located?located?

This map shows how the epicenter of the Loma Prieta earthquake was determined using data from three seismic stations. The seismogram at Eureka, CA indicated that the epicenter was 478 km away (red circle). The green circle represents the distance of the epicenter (624 km) from Las Vegas. The blue circle represents the distance of the epicenter (702 km) from Elko, NV. The epicenter is determined by the intersection of all three circles near Santa Cruz, CA. This triangulation technique requires data from at least three seismic stations in order to determine the epicenter.

http://www.sci.csuhayward.edu/best/Sat00-01/EarthquakeWorkshop/graphics/NCalLocation.gif


Earthquake MeasurementEarthquake Measurement► Magnitude is a measure Magnitude is a measure

of of ENERGY RELEASED ENERGY RELEASED IN AN EARTHQUAKEIN AN EARTHQUAKE Measured by a Measured by a RICHTER RICHTER

SCALESCALE

► Intensity is the amount of Intensity is the amount of DAMAGEDAMAGE an earthquake an earthquake causescauses Measured by the Measured by the MERCALLI MERCALLI

SCALESCALE


Lecture 6.2Lecture 6.2► Big Idea Question #2Big Idea Question #2

What is the difference between intensity and magnitude? What is the difference between intensity and magnitude? What scales are used to measure each?What scales are used to measure each?

► End of Chapter Questions End of Chapter Questions p. 112-113 #8-11p. 112-113 #8-11


TEST QUESTION:TEST QUESTION:Circle on the diagram the location Circle on the diagram the location

of the epicenterof the epicenter

The seismogram in Pusan, Korea indicated that the epicenter was 549 km away (red circle). The green circle represents the distance of the epicenter (435 km) from Tokyo. The blue circle represents the distance of the epicenter (697 km) from Akita, Japan. The epicenter is determined by the intersection of all three circles in Kobe. This triangulation technique requires data from at least three seismic stations in order to determine the epicenter.

05/03/23 identify changes in the earth’s crust that may signal earthquakes

Essential Questions Chapter Essential Questions Chapter 6 Section 36 Section 3

►Describe the possible effects of a major Describe the possible effects of a major earthquake on buildingsearthquake on buildings

►Discuss the relationship of tsunamis to Discuss the relationship of tsunamis to earthquakesearthquakes

►List safety rules follow when an List safety rules follow when an earthquake strikesearthquake strikes

► Identify changes in the earth’s crust that Identify changes in the earth’s crust that may signal earthquakesmay signal earthquakes


Describe the possible effects of Describe the possible effects of a major earthquake on buildingsa major earthquake on buildings► Earthquake DamageEarthquake Damage► Most injuries, result of Most injuries, result of

collapsing buildings or collapsing buildings or falling objects.falling objects.

► Types of damage – Types of damage – landslides, fires, broken landslides, fires, broken gas and electric lines, gas and electric lines, flooding, and damage to flooding, and damage to damsdams

► The longer an earthquake The longer an earthquake last the more damage it last the more damage it causescauses


Describe the possible effects of Describe the possible effects of a major earthquake on buildingsa major earthquake on buildings► Destruction to Destruction to

buildings and buildings and propertyproperty

► Buildings are not Buildings are not designed to sway, designed to sway, walls can collapse, walls can collapse, may tip overmay tip over

► Type of ground, solid Type of ground, solid ground offers more ground offers more support to buildings, support to buildings, loose soil can cause loose soil can cause more swaying in more swaying in buildingsbuildings


Discuss the relationship of tsunamis to Discuss the relationship of tsunamis to earthquakesearthquakes

► TsunamisTsunamis ► Caused by underwater Caused by underwater earthquakes, that earthquakes, that either cause a either cause a landslide or faulting landslide or faulting underwater.underwater.

► Faulting can change Faulting can change seafloor elevation, seafloor elevation, forcing the water to forcing the water to move up and down.move up and down.

► Underwater landslide Underwater landslide can cause this same up can cause this same up and down motion.and down motion.


Discuss the relationship of tsunamis Discuss the relationship of tsunamis to earthquakesto earthquakes

► TsunamisTsunamis► There is an early There is an early

warning system to warning system to alert areas of alert areas of tsunamis.tsunamis.


List safety rules follow when an List safety rules follow when an earthquake strikesearthquake strikes

► Earthquake SafetyEarthquake Safety► Before an earthquakeBefore an earthquake

Be prepared – have Be prepared – have canned food, bottled canned food, bottled water, flashlights, water, flashlights, batteries and a batteries and a portable radio.portable radio.

Plan what to do when Plan what to do when a earthquake happensa earthquake happens

Learn how to turn off Learn how to turn off gas, water and gas, water and electricity to the electricity to the house.house.



► Earthquake SafetyEarthquake Safety ► During an During an earthquakeearthquake Stay calm and get to Stay calm and get to

a safe positiona safe position Indoors – protect Indoors – protect

yourself from falling yourself from falling objects.objects.

Outside – stay away Outside – stay away from tall buildings, from tall buildings, power lines, bridges, power lines, bridges, or tunnels or tunnels



► Earthquake SafetyEarthquake Safety ► After the After the earthquakeearthquake Check for hazards, Check for hazards,

always wear shoes, always wear shoes, and avoid power and avoid power lineslines


Identify changes in the earth’s crust that Identify changes in the earth’s crust that may signal earthquakesmay signal earthquakes

► Earthquake Earthquake warnings & warnings & predictionspredictions

► Animals behavior & past earthquakes Animals behavior & past earthquakes used to predict future earthquakes, may used to predict future earthquakes, may be years offbe years off

► Fault stress measured to determine Fault stress measured to determine seismic gaps, to determine where a seismic gaps, to determine where a quake may happen.quake may happen.

► Instruments used to detect crust tilting, Instruments used to detect crust tilting, rock stress, water flow changes, electro rock stress, water flow changes, electro magnetic changes to predict magnetic changes to predict earthquakes.earthquakes.

► Decreases in P-wave speed may tell Decreases in P-wave speed may tell when a quake is coming.when a quake is coming.

► Most methods are not very reliable in Most methods are not very reliable in predicting an earthquakepredicting an earthquake

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2/11/2016discuss the elastic rebound theory California Science Content Standards Covered: ► Plate tectonics operating over geologic time has changed the