epicenter

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Finding an Epicenter of an Earthquake:

Finding an Epicenter of an Earthquake

What is an Epicenter?:

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.

Slide 3:

Seismograph Print-outs

Use the data from the recording stations::

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? 4:10

Use the data from the recording stations::

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? 3:20

Use the data from the recording stations::

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? 2:00

Difference in arrival times::

Difference in arrival times: San Francisco: 4:10 Denver, Colorado: 3:20 Missoula, Montana: 2:00

Slide 8:

WE TAKE A PIECE OF PAPER, AND MARK OFF THE DIFFERENCE IN ARRIVAL TIME 2800Km 4:10

Slide 9:

WE 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

EPICENTER DISTANCES:

EPICENTER DISTANCES San Francisco: 4:10 Denver, Colorado: 3:20 Missoula, Montana 2:00 2,800km 1,100km 2,000km

Recording Board Difference in arrival times::

Recording Board Difference in arrival times: San Francisco: 4:10 =2,800km 1,000 2,000 3,000 4,000 5,000 Open your compass to the EXACT distance on the scale.

Slide 12:

. . . Use your carefully set compass to draw a circle around each city. You've found the epicenter! 2,800km 2,000km 1,100km