Science Do Now: 12-10

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ScienceDo Now 12-10

• HW COMPLETE THE QUESTIONS FROM TODAYS NOTES
• Stack your grade report if it needs to be turned
  in today.
• Stack your Do Now sheets for collection
• Open text book to page 230
• Today
• Power Point w/notes Measuring Earthquakes

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Measuring Earthquakes
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Did you hear about any earthquakes that occurred
today?

• USGS- EARTHQUAKE INFORMATION

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Locating Earthquakes

• Seismic waves are
• detected at
• seismographic
• stations located
• around the world
• They are located
• at or near the
• Earths surface

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How does a seismograph work?

• Seismograph records ground movements of
  earthquakes
• The pendulum sits still while the rotating drum
  and ground moves.
• Seismogram shows
• the earthquake
• motion.

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Where is the center of an earthquake?

• Focus Point where rocks break UNDERGROUND
• Epicenter Center of earthquake ABOVE GROUND

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The S-P MethodLocating an Epicenter

• Distance to the epicenter is measured on a
• time-distance graph.
• It takes THREE seismograph stations to locate an
  epicenter. A circle is drawn around each
  location. The epicenter is where the 3 circles
  overlap.

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Epicenters from 1977 - 1996
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Earthquake Scales

• There are two different scales used to measure
  earthquakes
• The Richter Magnitude Scale
• The Modified Mercalli Intensity Scale

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The Richter Scale

• Measures the amount of ground motion.
• Ranks from 1-10
• Each 1 point jump increases the ground motion 10
  times!!
• Measured using a seismograph

Magnitude Estimated effects 2.0 can be
detected only by seismograph 3.0 can be felt
at epicenter 4.0 can be felt by
most people in the area
5.0 causes damage at epicenter
6.0 can cause widespread damage
7.0 can cause great, widespread damage
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The Mercalli Scale

• Ranks from 1-12 with Roman Numerals
• Measures the intensity which
• DAMAGE
• One Earthquake can have more than one intensity
  level

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What are the worst earthquakes ever recorded?