Has anyone thought about using an abandoned water truck (tank only)? You would have more space inside for both you and your supplies. If it was buried 2/3 of the way up it would have a very good chance of holding up during the pole shift. It may be costly to buy and transport a used tank, not to mention digging it in, but much cheaper than building a dome house. If you went one cheap step further you could surround the tanks with concrete or RASTRA, thereby making your instant shelter that much more sturdy.
This brings up another idea; What if you were to connect four of these tanks to each other in the form of a square? Each tank would make up one side of the square with hatches cut into the ends to enable a person to walk through into the next tank. If each tank has a hatch cut into the top as well (one that only opens from the inside) then you have a better chance of avoiding having your only exit blocked by debris and turning your survival shelter into a coffin.
Offered by Doug.