seismic wave basics. finding an epicenter what is an epicenter? a point on the surface of the earth...
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![Page 1: SEISMIC WAVE BASICS. Finding an Epicenter What is an Epicenter? A point on the surface of the Earth directly above the FOCUS of the earthquake. The point](https://reader036.vdocuments.site/reader036/viewer/2022062805/5697bfc41a28abf838ca6011/html5/thumbnails/1.jpg)
SEISMIC WAVE BASICS
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Finding an Epicenter
![Page 3: SEISMIC WAVE BASICS. Finding an Epicenter What is an Epicenter? A point on the surface of the Earth directly above the FOCUS of the earthquake. The point](https://reader036.vdocuments.site/reader036/viewer/2022062805/5697bfc41a28abf838ca6011/html5/thumbnails/3.jpg)
What is an Epicenter?• A point on the surface of the Earth directly
above the FOCUS of the earthquake.
•The point within the Earth from which earthquake waves originate.
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![Page 5: SEISMIC WAVE BASICS. Finding an Epicenter What is an Epicenter? A point on the surface of the Earth directly above the FOCUS of the earthquake. The point](https://reader036.vdocuments.site/reader036/viewer/2022062805/5697bfc41a28abf838ca6011/html5/thumbnails/5.jpg)
Use the data from the recording stations:
• Station A: San Francisco, California
P-Wave arrival 3:02:20 S-Wave arrival 3:06:30
What is the time difference between P and S wave arrivals?
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Use the data from the recording stations:
• Station B: Denver, Colorado
P-Wave arrival 3:01:40 S-Wave arrival 3:05:00
What is the time difference between P and S wave arrivals?
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Use the data from the recording stations:
• Station C: Missoula, Montana
P-Wave arrival 3:01:00 S-Wave arrival 3:03:00
What is the time difference between P and S wave arrivals?
![Page 8: SEISMIC WAVE BASICS. Finding an Epicenter What is an Epicenter? A point on the surface of the Earth directly above the FOCUS of the earthquake. The point](https://reader036.vdocuments.site/reader036/viewer/2022062805/5697bfc41a28abf838ca6011/html5/thumbnails/8.jpg)
Difference in arrival times:
San Francisco: 4:10
Denver, Colorado: 3:20Missoula, Montana: 2:00
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TAKE A PIECE OF PAPER, AND MARK OFF THE DIFFERENCE IN ARRIVAL TIME
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MOVE THE PAPER UNTIL THE TWO TICK MARKS LINE UP WITH THE P AND S CURVES
WHEN TICK MARKS LINE UP, GO STRAIGHT DOWN AND READ THE EPICENTER DISTANCE
EPICENTER DISTANCE OF 2800 KM
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EPICENTER DISTANCES
San Francisco: 4:10
Denver, Colorado: 3:20Missoula, Montana 2:00
2,800km
1100km
2,000km
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Recording BoardDifference in arrival times:
San Francisco: 41:02,800km
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Open your compass to the EXACT distance on the scale.
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