Which scenario describes a “soft storey” building collapse?

Which scenario describes a “soft storey” building collapse?

1. a building is shaken off its first-floor posts, obliterating everything in that first floor space
2. two adjacent buildings shake at different frequencies, causing damage in the area where they collide
3. a 100-year-old 3-story wooden structure collapses completely
4. a building topples over because one side of its foundations sinks into ground softened by liquefaction
5. brickwork on the face of a building is shaken off into the street