How much damage would there be from a 7.5 to 8.0 quake on the San Andreas fault ?

If it happens near the surface and near a populated area some very serious damage. If the focus of the earthquake is located several miles down in the ground much less. Also if it happens away from a populated area there would be less damage. Some years back there was a big 7.0 quake that happened out in the desert over 70 miles east of Los Angles that barely did any damage to populated areas.