What was the underground railroad?

In a 2010 article “fact check: eastern u.s. earthquake risk” by chris mould, the author provides as evidence the following statement by the united states geological survey: “although earthquakes may be less frequent in the eastern u.s., … urban areas in the east could face bigger losses because the shaking would affect much larger areas than similar quakes in the west. in addition, most homes and buildings in the east are not designed to withstand earthquakes.”this statement directly relates to which of the following concepts? a. vulnerabilityb. hazardc. riskd. severity