How We Perceive Earthquakes (i.e Intensity)

Intensity

• how we perceive earthquakes (the intensity we feel) depends on several factors…

  1. magnitude:

     1. lower magnitude = less intense

     2. less energy, waves less powerful

     3. shorter shaker time

  2. distance from epicenter

     1. further = less intense

     2. seismic waves attenuate (weaken) as they travel

  3. duration (how long)

     1. shorter = less intense

     2. larger earthquakes can have several minutes of shaking

  4. foundation (ground) material

     1. solid rock = least intense
     2. well-compacted sediment = less intense
     3. water-saturated sediment = more intense (potential for liquefaction)

  5. building structure (building reaction to ground acceleration)

     1. in general:

     2. brick and concrete = bad

     3. wood, steel, and reinforced concrete = good

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