seismic waves and the shadow zone. sudden release of energy in the earth’s crust and creates...
TRANSCRIPT
![Page 1: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/1.jpg)
Anatomy of an Earthquake
Seismic waves and the shadow zone
![Page 2: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/2.jpg)
What are Earthquakes? Sudden release of energy in the
Earth’s crust and creates seismic waves. • Occurs naturally or human induced.
![Page 3: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/3.jpg)
What is the anatomy of an earthquake?
Faulting: most common cause of earthquakes Focus: Point below the surface where rocks
break and move (underground point of origin) Epicenter: Directly above the focus at surface
(most violent shaking occurs here)
![Page 4: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/4.jpg)
What are the 3 types of Seismic Waves?
Three types of seismic waves• 1. Primary (P waves)• 2. Secondary (S waves)• 3. Surface (L waves)
![Page 5: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/5.jpg)
What are Body waves? P waves
• Fastest• Travel through solid, liquid, and gas• Push pull waves• Moves through the core and faster through
dense material S waves
• Arrive after P waves (slower)• Travel only through solids• Particles move side to side• Shake waves
![Page 6: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/6.jpg)
What are Surface waves? L waves
• Slowest• Originate at the surface (epicenter)• Move up and down like ocean waves• Cause the most damage
![Page 7: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/7.jpg)
What is a Shadow Zone? A shadow zone is an area of the earth that is
"shadowed" by the planet's internal structure, in that it doesn't receive seismic waves.
Seismic waves will bend and reflect at the interfaces between different materials• P waves will travel and refract through both fluid and
solid materials. S waves, however, cannot travel through fluids like air or water.
![Page 8: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/8.jpg)
What do seismographs measure?
Seismographs record earthquake waves
Seismograms show:• Amplitude of seismic waves (how
much rock moves or vibrates)
• Distance to the epicenter
• Earthquake direction
![Page 9: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/9.jpg)
![Page 10: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/10.jpg)
How do I read a seismograph?
• P & S waves used to calculate magnitude of earthquake
• Amplitude = height of wave (how much the rock moves; size of vibration)
P & S (body waves) move through earth & arrive first
![Page 11: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/11.jpg)
How do we find the epicenter of an earthquake?
Exact location can be known by using three seismic stations or triangulation.
![Page 12: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/12.jpg)
The time interval between the arrival of the first P wave and S wave determines distance to epicenter. • The longer the “lag” the farther away the epicenter is.
![Page 13: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/13.jpg)
What is the difference between an intensity scale and
magnitude scale? Intensity Scales: measure the degree of
shaking and amount of DAMAGE done• Modified Mercalli
Magnitude scale: relies on calculations of estimated energy released by seismic waves. • Richter Scale• Moment Magnitude scale
Increases by a factor of 10
![Page 14: Seismic waves and the shadow zone. Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced](https://reader038.vdocument.in/reader038/viewer/2022103123/56649d215503460f949f70af/html5/thumbnails/14.jpg)
Mercalli vs Richter