M A S T E R P A G E
5. Supposing that volume of ocean water is lifted an average height (d) of one meter, how much work (W) is
done? This value represents the energy imparted to the seismic sea wave by the earthquake.
Distance lifted: d = 1 m
Work done against gravity:
W = Fd = (7.6 x 10
17
N)(1 m) = 7.6 x 10
17
Joules.
6. How much energy is this in equivalent tons of TNT?
Conversion factor: 4.18 x 10
9
Joules = 1 Ton TNT
W = Energy = (7.6 x 10
17
Joules) (1 Ton TNT/4.18 x 10
9
Joules)
Energy = 1.8 x 10
8
Tons TNT or 180 Megatons TNT
7. Imagine this much energy spreading over a great area, but then being applied to say only 3.8 meters of water
instead of 3.8 kilometers. How high might the 3.8 meters of water be lifted?
If all the energy were applied to only 3.8 meters of water (1/1,000
th
), then the water would rise 1,000 meters
instead of only one meter. The energy spreads out very rapidly, so maybe only 1/100
th
of the energy reaches the
3.8 meters of water. In this case the water would rise 30 meters—quite a sizeable wave.
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