State authorities and hospital officials have discovered serious structural weaknesses at more than a dozen hospital buildings, but they have taken few steps to notify the public about the facilities or require a detailed inventory of hundreds of other potentially dangerous sites. More than a dozen hospital buildings in the Bay Area and Southern California face the highest-known chances of crumbling during an earthquake, based on a complex mash-up of each building’s structural strength, distance from a fault line and expected ground motion, California Watch has learned. While the problem of hospital safety has been widely debated, few people know how little California is doing to detect its riskiest hospital buildings. Regulators do not require hospital owners to determine a collapse risk for every building they own, making it impossible to know which should be fixed first.