Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below...
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Transcript of Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below...
![Page 1: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/1.jpg)
Earthquake WavesChapter 6-2
![Page 2: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/2.jpg)
Focus and epicenter
Actual location of faultUp to 700 km below surface
![Page 3: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/3.jpg)
Focus and epicenter
Surface location directly above the focus
Actual location of faultUp to 700 km below surface
![Page 4: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/4.jpg)
P-waves
Primary waves- Compression waves
- Travel in a horizontal direction
- First to arrive at a distant location
![Page 5: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/5.jpg)
S-waves
• Secondary waves
- vibrate at right angles
to p-wave
- particles move back
and forth but wave
moves forward
- second to arrive at
distant location
![Page 6: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/6.jpg)
Surface Waves
• Surface waves- travel parallel to Earth’s surface- have greatest height- move like an ocean
wave- last to arrive at
distant location
- are responsible for damage
![Page 7: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/7.jpg)
Locating Epicenter• Time lag between P-wave and S-wave indicate
how far the earthquake is from a seismograph station.
Lag Time
![Page 8: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/8.jpg)
Locating Epicenter
• The lag time tells us how far we are from an earthquake but not from which direction
Epicenter can be any where on radius of the circle
![Page 9: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/9.jpg)
Locating Epicenter
• At least ____ seismograph stations are needed to pinpoint the epicenter of an earthquake
Infinite number of possibleepicenters
![Page 10: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/10.jpg)
Locating Epicenter
• At least ____ seismograph stations are needed to pinpoint the epicenter of an earthquake
Possibleepicenter
Possibleepicenter
Two seismograph stations narrow possible epicenters down to two
![Page 11: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/11.jpg)
Locating Epicenter
• At least three seismograph stations are needed to pinpoint the epicenter of an earthquake
Three epicenters narrows possible locations down to one
epicenter
![Page 13: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/13.jpg)
Measuring Earthquakes
• Mercalli Scale- rates earthquake
according to level of
damage at a given
location
- 12 steps to scale
- same earthquake can
have different rating at
different locations
![Page 14: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/14.jpg)
Measuring Earthquakes
• Richter Scale- rates earthquake’s
magnitude based
on size of seismic
waves
- works well with
small, nearby
quakes
- waves are
measured by a
seismograph
![Page 15: Earthquake Waves Chapter 6-2. Focus and epicenter Actual location of fault Up to 700 km below surface.](https://reader031.fdocuments.in/reader031/viewer/2022032307/56649cf05503460f949beb4a/html5/thumbnails/15.jpg)
Measuring Earthquakes• Moment Magnitude
Scale- estimates the total
energy released by an earthquake
- can rate all earthquakes- scientists look at type
and strength of waves, amount of movement, and strength of rocks that broke