The typical concrete block foundation is 8” thick and has no reinforcing steel. Such walls have a minimum allowable back fill height (outside soil height) of 5’-0”. It is very common to find such foundations with back fill height of 6’-7’ and more. The concrete block can shift. Cracks in the horizontal mortar joints indicate shifting due to lateral soil pressure. If cracks should appear, it will be necessary to reinforce the foundation walls.