(II) The intensity of an earthquake wave passing through the Earth is measured to be $3.0 \times 10^{6} \mathrm{J} / \mathrm{m}^{2} \cdot \mathrm{s}$ at a distance of 48 $\mathrm{km}$ from the source. (a) What was its intensity when it passed a point only 1.0 $\mathrm{km}$ from the source?
(b) At what rate did energy pass through an area of 2.0 $\mathrm{m}^{2}$ at 1.0 $\mathrm{km}$ ?