Reclaimed land
I saw a lot of the results of liquefaction at Treasure Island from the 89 earthquake when asked to give a bid on making road detours. The ground sunk to 12" in some places. A lot of the buildings had to have new steps built because the ground sunk but the buildings didn't or at least as much. It was interesting that the fire hydrants didn't sink but the area around them did including the roads.
You can see liquefactions areas mapped at USGS.