$5.-.$ A $2\mathrm{.}0-m-$thick loose sand layer with $15\%$ fines exists at the depth starting from $3\mathrm{.}0m.$ The groundwater table is at $0\mathrm{.}5m$ from the ground surface. The unit weights of the sand above and below the groundwater are $17\mathrm{.}4$ and $18\mathrm{.}1k\frac{N}{m}3,$ respectively. The SPT N$60$ values at the depths of $3\mathrm{.}5$ and $4\mathrm{.}5m$ are $10$ and $11\mathrm{.}5,$ respectively. The site is located at a seismically active area with a possible maximum magnitude earthquake of $7\mathrm{.}8$ and a peak ground acceleration of $0\mathrm{.}35g.$ Calculate the factor of safety of this sand against liquefaction and the seismically induced settlement.