The intensity of an earthquake wave is measured to be 6 x10 ^6 J ms at a distance of 50 km from its source. Calculate the intensity when it passed the point 4 km to source ? What is the rate energy passed through an area of 6 ms^2 at 4 kW?

Question

The intensity of an earthquake wave is measured to be 6 x10 ^6  J ms at a distance of  50 km from its source.  Calculate the intensity when it passed the point 4 km to source ? What is the rate energy passed through an area of 6 ms^2 at 4 kW?

drwls · Answer

I am confused by your units. m s^2 is not a measure of area. I never heard of J ms as a mesure of intensity. Another problem I have with this question is whether or not to assume an inverse square law for the falloff of intensity with distance. Some kinds of waves that are confined to regions near the Earth's surface may fall off less rapidly that that. Your question does not say what kind of waves are involved.