Nothing in this chapter shall prevent the restoration of a nonconforming use or structure partially destroyed by fire, explosion, act of God or act of public enemy, provided that any nonconforming use or structure partially destroyed in the manner aforesaid may be reconstructed and thereafter used only in such manner as to not further violate the reasons for nonconformity. Any nonconforming use or structure totally destroyed in the manner aforesaid may only be rebuilt as a conforming use or structure.