According to the LA Times, L.A.’s rating system would involve some type of scientific assessment that would rank the safety of various buildings. "Grading the quake risk would be a huge undertaking. The city would first have to agree on a standard for evaluating buildings. Then it would have to come up with a process for inspecting each building, a task that could be long and complicated. Finally, officials would need to decide how to publicize the grade, either using a placard at buildings like the restaurant health grading system or on a website," the report said.

According to the  LA Times, a rating system developed by the U.S. Resiliency Council, a volunteer group of structural engineers, could serve as a model. That system uses a 1 to 5 star system.

A 1-star building would warn of multiple, widespread deaths, and 2-stars would warn of deaths in isolated areas. Three-stars would mean no deaths, four-stars no injuries, and five-stars would mean no one would be expected to be trapped. The stars could be posted in the lobby.

As previously reported by Security magazine, the city of San Francisco Planning and Urban Research Assn. in 2009 proposed a similar program using letter grades. “A” grades would mean buildings would be operational after a quake; “B” would be usable while repairs were made, while “C” buildings would have to be vacated during repair. “D” buildings wouldn’t cause fatalities but would be unrepairable, while “E” structures would be the most unsafe.

http://www.latimes.com/local/lanow/la-me-ln-garcetti-wants-la-buildings-to-be-graded-for-earthquake-safety-20140411,0,6736114.story#ixzz2yn8vCbJo