Hazard is the description of what the earth might do.
Risk is the description of economic loss.
With these definitions, then, we say that the Reno - Carson area has the highest hazard because the probability of strong earthquake shaking is much higher there than in Las Vegas. On the other hand, with a population nearly three times that of the Reno-Carson area, and with structures built to a lower standard because the hazard is lower, estimates of the average annual economic loss in Los Vegas are higher, explaining why the risk is higher.
