What are cripple walls?  A cripple wall is simply a short stud wall that extends from the top of the perimeter foundation upward to carry the floor joists. The potential danger comes from the fact that these components are in the seismic load path, and are often inadequately braced. They can hinge over and collapse like dominos in a large earthquake. 

Cripple Wall Diagram #1

Take care: not all homes have cripple walls, but that won’t stop opportunistic contractors from offering to brace them.

Another View of a Cripple Wall

Click here for a framing anchor diagram