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

                 1. less energy, waves less powerful         2. shorter shaker time   2. distance from epicenter

           1. further = less intense

                 1. seismic waves attenuate (weaken) as they travel   3. duration (how long)

           1. shorter = less intense

                 1. 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:

                 1. brick and concrete = bad         2. wood, steel, and reinforced concrete = good

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