Earthquake Prediction Methods

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Earthquake Prediction Methods
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Earthquake predictions

• Because earthquakes do not happen on regular
  intervals it is difficult to predict when the
  next one will occur.
• Methods for predicting earthquakes on these
  faults vary none of them being 100 accurate.
• Predictions are given for a time frame instead of
  an exact date.

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Why is it important?

• http//www.teachersdomain.org/resource/ess05.sci.e
  ss.earthsys.japan/
• Early prediction theories were based on patterns,
  and timing between earthquakes

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Are Earthquakes Getting More Frequent?
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Earthquake Fatalities Since 1800
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Statistical Methods

• Must collect data on location and magnitude of
  earthquakes
• okay for smaller earthquakes but not for larger
  earthquakes.
• This data is used in several statistical
  predictions

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Statistical Methods

• Recurrence Frequency
• Looks for relationship between the magnitude and
  repetition of earthquakes.
• Assumes that the same set of conditions leading
  to an earthquake occur each time.
• Dependent on large amounts of historical data.

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Statistical Methods

• Seismic Gap Theory
• A seismic gap is an area along a fault where
  there has not been any earthquake activity for a
  long period of time.
• Focuses on patterns in seismicity..
• If a change in the pattern occurs, there is a
  chance for an earthquake.

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Physical measurements

• Events that occur before an earthquake can
  include
• Increase in the rate of seismic creep
• Gradual tilting of the land near the fault zone
• Drop or rise in the water level of a well
• Decrease in the number of foreshocks
• Dramatic changes in animal behavior

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Physical measurements

• Fault Creep Measurements
• Measures the slow rate of movement at the fault.
• Lots of fault creep means a small chance of a big
  earthquake.
• Low amounts of fault creep means a high chance of
  a big earthquake.

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Physical measurements

• Drop or rise in the water level of a well
• Large surface waves force particles of rock near
  to the surface which changes water levels in a
  well.
• Water levels can be affected by any fault creeps,
  crust tilts, or other seismic activity.
• We can drill wells in certain locations to
  measure dramatic changes in water levels.

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Physical and Geophysical measurements and
observations

• Animal behavior
• unusual animal behavior can be a way to predict
  earthquakes
• The Chinese started recording unusual animal
  behavior and successfully predicted an earthquake
  in 1975 3 months before it struck.

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Physical and Geophysical measurements and
observations

• Unusual animal behavior includes
• Hibernating animals leaving their underground
  nests
• Animals refusing to go into pens
• Animals seeking higher ground
• Birds vacating the area
• Deep water fish come closer to the surface

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Physical measurements

• This type of prediction requires a lot of data
  collection and review to find patterns.
• Problem with this method is that some of
  characteristics are geographically specific so
  they cannot be applied to different areas.

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Conclusion

• Predicting earthquakes is not yet possible
• The more data we review and the more patterns we
  find the better the predictions