Locating Earthquakes

​Earthquakes

Earthquakes are caused when underground rock along a fault line suddenly slip/break, causing rapid motion along the fault.

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This sudden release of energy creates seismic waves. Seismic waves spread out in every direction and cause the ground to shake.

​Earthquakes

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• ​Slower moving waves

• Only move through solids (Earth's crust)​

• Move the ground up and down ​or side-to-side (create the shaking feeling)

​S - Waves:

• ​Fast moving waves

• Move through solids, liquids, & gases

• Move in a coiled pattern causing a spring-like motion

​P - Waves:

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​Earthquakes create two types of seismic waves

Multiple Choice

S-Waves are . . .

• Fast moving waves that move through solids, liquids, and gases

• Slow moving waves that travel through solids.

Multiple Choice

P-Waves are . . .

• Fast moving waves that move through solids, liquids, and gases

• Slow moving waves that travel through solids.

Multiple Choice

S-Waves move . . .

• In an up-and-down and side-to-side motion, causing the ground to shake

• In a coiled motion, causing sprig-like action

Multiple Choice

P-Waves move . . .

• In an up-and-down and side-to-side motion, causing the ground to shake

• In a coiled motion, causing sprig-like action

The focus is the point inside the Earth's crust where the earthquake originated from.

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​Focus & Epicenter

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​The epicenter i​s the point above Earth's crust where the earthquake originated from. The Epicenter is directly above the focus!

Multiple Choice

The point where an earthquake originated from inside the crust (deep underground) is called?

• The Focus

• The Epicenter

Multiple Choice

The point where an earthquake originated from above the crust is called?

• The Focus

• The Epicenter

Seismologists use the process of triangulation to determine the epicenter of an earthquake. 

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Seismologists first determine when P-waves arrive to a seismograph. They then will count how long it takes for the S-waves to arrive to the same seismograph. Scientists then take this data from 3 seismographs and put it together to find the epicenter. The longer it takes the S-waves to arrive, the farther away the epicenter of the earthquake is from a seismograph

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​Triangulation

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​The Richter Scale

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​Measures the magnitude of an earthquake

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The magnitude is the maximum motion/energy of an earthquake

​Moment of Magnitude Scale: 

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​Measures the total amount of energy released 

​The Modified Mercalli Scale:

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​Uses roman numerals to express intensity (damage to surfaces) of an earthquake 

Multiple Choice

A moderate earthquake occurred. Between what 2 numbers on the Richter Scale could this earthquakes magnitude have been rated at?

• 2.5 - 5.4

• 6.1 - 6.9

• 5.5 - 6.0

• 7.0 - 7.9

Multiple Choice

An earthquake occurred. It was at a V. intensity (green). It could be felt by nearly everyone. Some dishes and windows may have been broken. 

What level of shaking occurred?

• Light

• Moderate

• Strong

• Very Strong