Rotation is usually caused when the soil under the outside of the foundation is saturated with moisture while the soil in the crawl space is dry.  When the soil on the outside becomes soft and saturated the foundation starts to sink on the outside edge.  Poor drainage is the cause of this 100% of the time.  Very rarely the foundation will rotate inwards towards the crawl space.  It is my experience that in these cases the drainage under the house was worse than the drainage o the outside.   In either case, rotated foundations can be bolted to the house just as effectively as with foundations that have not rotated.  Rotated foundations, unless the rotation is so extreme that the building will soon lose vertical support, has ZERO impact on a foundation’s ability to hold a house up off the ground or its ability to perform in an earthquake so long as you attach the house to it with a retrofit.