G8 Science Q2- Week 3-Seismic-Waves.pptx

Science 8 quarter 2 Identify the different types of Seismic Waves

1. Seismic Waves PREPARED BY: TYPE YOUR NAME HERE

2. How Earthquake Waves Provide Information about the Interior of the Earth

3. S8ES - IIc - 17 Explain how earthquake waves provide information about the interior of the earth

4. ` Seismic Waves These are the waves of energy caused by the sudden breaking of rock within the earth or an explosion. They are the energy that travels through the earth and recorded on seismographs.

5. ` Types Seismic Waves Body waves -  arrive before the surface waves emitted by an earthquake. These waves are of a higher frequency than surface waves. Surface waves(L-Waves) - are of a lower frequency than body waves, and are easily distinguished on a seismogram as a result. Though they arrive after body waves, it is surface waves that are almost entirely responsible for the damage and destruction associated with earthquakes. This damage and the strength of the surface waves are reduced in deeper earthquakes.

6. ` Body Waves Primary Waves Secondary Waves push and pull side to side

7. ` Primary Waves Primary waves are “compression waves”. They push and pull the rocks of the earth's surface. They can move through solid rock and fluids like water or the liquid core layers of the earth And first to 'arrive' at a seismic station.

8. ` Secondary Waves Secondary waves travel slower than primary waves. Also called “shear waves "or “Transverse Waves”. They create a side to side motion in the rocks through which they are traveling.

9. ` Secondary Waves Unlike the other earthquake waves, S-waves cannot travel through water or the liquid rock of the Earth's core layer. They can Travel through solid only-waves will rock buildings side-to-side.

10. ` Remember... Primary Waves Secondary Waves Also Called as Compression Waves . They Push and Pull the rock in the earth’s surface. Also Called as Shear/Transverse Waves . They rock the earth’s surface Side to Side .

11. ` Surface Waves(L-Waves) Love Waves Rayleigh Waves

12. ` Surface Waves(L-Waves) Land waves move along the surface of the earth and cause it to move up and down like something bobbing on the surface of the ocean.

13. ` Surface Waves(L-Waves) Land waves only move along the surface of the earth. Their speeds vary depending on the material, rock or soil, forming the surface. These waves cause the surface to move up and down . These are the waves that cause the buildings and other structures during an earthquake destroy.

14. ` Named after A.E.H. Love, a British mathematician who worked out the mathematical model for this kind of wave in 1911.  Love Waves most damage Love waves travel with a lower velocity than P or S waves, but faster than Rayleigh waves. These waves travels in lithosphere only.

15. ` These waves are a type of surface acoustic wave that travel on solids Rayleigh Waves Named for John William Strutt, Lord Rayleigh, who mathematically predicted the existence of this kind of wave in 1885.  Rolls along the ground just like a wave rolls across a lake or an ocean. Because it rolls, it moves the ground up and down, and side-to-side in the same direction that the wave is moving.  Most of the shaking felt from an earthquake is due to the Rayleigh wave, which can be much larger than the other waves.

16. ` Remember... Love Waves travels through lithosphere only. Has Low Velocity but faster than Rayleigh waves. Rayleigh Waves travel on solids and Rolls along the ground

17. ` Types of Waves

18. ` How Earthquake Waves Provide Scientists with information About the Nature and Composition of the Earth Seismic waves provide the information about the earth’s internal structures. 2. Seismographs were being set up around the world to analyze and track the movement of earth’s crust. 3. Body waves, P-waves and S-waves can propagate deeply beyond the earth’s crust and they are used to determine what is in the inner part of the earth.

19. ` Factors considered by the seismologists in mapping the inner layers of the earth: The properties of materials that a wave passes through. 2. Time of arrival of the waves at the seismic station. 3. The speed at which the wave travels through different materials. 4. Reflection and refraction of seismic waves.

20. ` The following are some of the information which the seismologists have acquired using the seismic waves to reveal what is inside the earth. Seismic waves are generally traveling with depth as they move faster through denser materials. 2. P-waves are known for being the fastest waves, and they arrive first at the seismic station but become slower when they travel in fluids. Seismic waves move slower in hot areas.

21. ` The following are some of the information which the seismologists have acquired using the seismic waves to reveal what is inside the earth. P-waves move slowly in partially molten areas of the earth while S-waves are stopped at this region because of the shearing motion that cannot be transported through liquids. This only shows the zone where mantle is closer to its melting point at its depth and pressure and the seismic waves are at the asthenosphere.

22. ` The following are some of the information which the seismologists have acquired using the seismic waves to reveal what is inside the earth. When a wave arrives late at the seismograph, it means it passed through a hot and semi-fluid part of the earth. 3. S-waves cannot penetrate the core-mantle boundary and the p-waves are refracted in the molten layer of this region of the outer core.

23. ` The following are some of the information which the seismologists have acquired using the seismic waves to reveal what is inside the earth. 4. p-wave velocities suddenly increase upon reaching the inner core which consists of solid materials and there is no evidence of S-waves. 5. The farther away from the epicenter (earth’s surface), the larger the gap in the time between the arrival of P- and S-waves at the seismic station.

24. ` The following are some of the information which the seismologists have acquired using the seismic waves to reveal what is inside the earth. 6. The “shadow zone” is developing on the opposite side of the earth once the S-waves pass through the liquid core and where the S-waves are detected. 7. Some P-waves are reflected off along the boundary between the inner and the solid core.

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