Buildings will often experience minor cracking during earthquakes, and sometimes will experience significant cracking that indicates the building is severely damaged and in danger of collapse. How do you know the difference? An evaluation by a structural engineer is needed to be certain, but one clue is to look at the shape of the cracks. Simple line cracks are often just in the stucco. An X-shaped crack is more serious. It can indicate that the whole wall is shifting and may represent significant damage to the building.