I cannot comment on the other cities in the top 10, but I work in Seattle. I've been the King County Emergency Management Director (the county that Seattle is in). I've worked in emergency management in Washington state for 25 years, at the state and county level.
It might be that when compared to the rest of the cities in the nation, because they are so poorly prepared, that Seattle is highly rated. However, I know the risks, I know the level of interest in public safety and seismic safety in that city by their elected officials, especially when it comes to unreinforced masonry (URM) buildings. This includes government, business, nonprofits and everyone else you want to lump into the mix. That is not to say that Seattle Emergency Management is not doing a good job. They have a steep hill to climb and there is no one on the other end of the rope helping to pull them up. To back me up, see this Seattle Times investigative piece: Seismic Neglect.
All of the above calls into question the other nine cities on the list — in my opinion.