Setbacks from bluffs, banks and cuts shall be approved by the Building Official. Minimum setbacks from bluffs, banks and cuts declared unstable by published Soils Conservation Service Slide Hazard Area Studies, or by the 1978 Coastal Zone Atlas of Washington shall be the height of the bluff, bank or cut, not to exceed 100 feet, or as recommended by an approved soils engineer. Setbacks shall be measured from the rim or top of the bluff, bank or cut.