. >>> bob mckinzie asks the question is landfill good or bad? >> a bit later the decision in the past century that's still bearing consequences on san francisco's telegraph hill. >>> a month after the loma prieta earthquake, bob mackenzie set out to answer the question is landfill a good or bad thing. the answer he found is its depend. >> reporter: when san francisco decided to stage a great exposition in 1915 a piece of shoreline was filled and leveled and the glorious but temporary buildings of the world's fair erected. that piece of filled land became the neighborhood we now call the marina. last night's earthquake struck the marina suffered greater damage by far than other parts of the city. partly because the marina's landfill is largely sand and subject to a phenomenon called liquid faction. the sand supports the brick just fine until it's shaken. the water rises, the t fragile adhesion is broken and the soil becomes a kind of quick sand. much of san francisco's financial district is also built on landfill. but the damage there was much les