Triangulation

Bell Work 11-08-06

1. The distance from Seattle to Tucson

is roughly 1700 miles. How many

kilometers is that? (5280—don’t ask!)

2. What is the difference between

magnitude and intensity?

3. An earthquake in Tokyo has a

magnitude of 6.0 and an intensity of

VIII, what is the magnitude and

intensity as recorded in Tucson?

What’s in a Seismogram?

Where

does it

start?

Where’s

the

diddy?

Where’s

the

snoop?

Where’s the

Surface Wave?

So What?

• Stack seismographs together (100,000’s)

• Run the image through some computer filters

• Image the interior of the Earth

•Charge oil companies lot$ of CA$H!

Plate Tectonics

• Where are the earthquakes compared to

plate boundaries?

Plate Tectonics

• So do you suspect

any convergent

boundaries here?

Plate Tectonics

• So do you suspect any convergent

boundaries here?

Plate Tectonics

• What about any convergent boundaries

here?

Plate Tectonics

• How do we find the epicenter?

Travel Time

• Notice a pattern here?

Travel Time

• Why so much noise? Shadow Zones!

Triangulation

• Given the time travel graph, what can we

tell about P wave and S wave arrivals?

Triangulation

What does that information buy us?

Triangulation

• So let’s try this!

• Using the Time Travel Graph, figure out

how far away the earthquake was from

these seismographs:

1. 8 seconds between P and S wave arrivals

2. 9.75 seconds

3. 3 seconds

Triangulation

• Now lets triangulate!

1. Find the distance from the epicenter using

the Time Travel Graph

2. Adjust your compass so that the radius of

your circle is the same as the distance to the

epicenter

3. Draw a circle with the compass

4. Do the same for the second and third

seismographs

Triangulation

U.S. Map

L.A. 3.5 Seconds

Seattle, WA 4.0 Seconds

Montpelier, VT 3.4 Seconds

You Try!• Hartford, CT 6 seconds

• Dallas, TX 3.4 seconds

• Ft. Wayne, IN 4.8 seconds

• Where is the shakin’ going on?

Sumatra Earthquake 12-26-05

• Plate Motion

• Any guess on

the origin of this

Map?(Hint: Wegener’s Homies)


• What caused this Tsunami?


• Wave

propagation


• Vertical

movement

of surface


• Each circle is an earthquake, even the

little ones are serious quakes!

• Note the frequency and pattern of the

subsequent aftershocks

• The date and time are rolling on the

bottom of the frame

• PAY ATTENTION!

• kahler Affe

– Bald Monkey

• Felsen Herrn E

– Mr. E Rocks

• Schlaf des Muß nicht, der Clown ißt mich

– Must not sleep, the clown will eat me

• Warum tun wir dies?

– Why are we doing this?

Triangulation

Education

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