The most reasonable conclusion to draw from the classification of one location as having the "highest hazard" and another as having the "lowest hazard" is:
"There is more likely to be an earthquake in a 'highest hazard' location than in a 'lowest hazard' location."
This indicates that the probability of an earthquake occurring is greater in the area classified with the highest hazard, while the area with the lowest hazard has a significantly reduced likelihood. However, it does not guarantee that an earthquake will definitely occur in the highest hazard location or that one will never occur in the lowest hazard location.