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Predicting and Forecasting Earthquakes

Predicting Earthquakes

  • humans (including scientists) can’t predict earthquakes

    • no such thing as “earthquake symptoms”

    • risk assessment is better

Prediction vs Forecasting

  • prediction: when will the next megathrust earthquake of >M8 happen in the pacific northwest?

  • forecast: what is the likelihood that a megathrust earthquake of >M8 will happen in the pacific northwest in the next 100 years?

Forecasting Earthquakes

  • use evidence of past earthquakes

    • historical earthquakes

    • geologic record

  • to find frequency of past earthquakes (return period)

  • useful for long term, imprecise prediction (or forecasting)

  • leads up to preparedness and good construction practices

Earthquake Warning Systems - Japan

  • alarm goes out when P - Waves are detected by seismometers near the epicenter

    • linked to cellular networks, TV, and radio

  • warning time = difference between P and S - wave arrival time

    • seconds to minutes

Predicting Earthquakes

  • humans (including scientists) can’t predict earthquakes

    • no such thing as “earthquake symptoms”

    • risk assessment is better

Prediction vs Forecasting

  • prediction: when will the next megathrust earthquake of >M8 happen in the pacific northwest?

  • forecast: what is the likelihood that a megathrust earthquake of >M8 will happen in the pacific northwest in the next 100 years?

Forecasting Earthquakes

  • use evidence of past earthquakes

    • historical earthquakes

    • geologic record

  • to find frequency of past earthquakes (return period)

  • useful for long term, imprecise prediction (or forecasting)

  • leads up to preparedness and good construction practices

Earthquake Warning Systems - Japan

  • alarm goes out when P - Waves are detected by seismometers near the epicenter

    • linked to cellular networks, TV, and radio

  • warning time = difference between P and S - wave arrival time

    • seconds to minutes