Land ownership is not really absolute; it is always subject to the definitions of the local law and, ultimately, the whims of the government.
You don't have complete power over what you do to your land, because the government has the last word. On the other hand, without government, there is no land ownership because the definition and enforcement of land ownership is one of the most ultimate functions of any government, since the creation of first city-states (e.g. ancient Babylon).
So if the government permits you to dig that hole in the first place, then what happens in an earthquake depends on local legislation. I don't really know how it works e.g. in the U.S. but I would assume that the boundary of your piece of land is defined in relation to physical markers that are recorded with their geocoordinates, but if the lay of the land changes so that the markers move, then the boundary of your plot will also move. And this could mean that the size of your plot changes.
Where I live, for instance, there are old boundary stones (which would in an earthquake naturally move along with the land on which they are laid) and newer marker bolts attached to bedrock that serve as reference points for geodesic measurement purposes. Also, there are height markers; for instance, when I started to build my house, the city would send a guy with equipment and start from one of these markers and then tell me if the foundations of the house are at right elevation. Should there be a major earthquake (not really a possibility here, ours is just about the most stable bedrock on Earth) then the changed positions (coordinates) would have to be recorded in land registry.
Thanks, these were interesting reads, although I would still appreciate a hint how common law specifically would handle emergence of new land differently from civil law systems?
You don't have complete power over what you do to your land, because the government has the last word. On the other hand, without government, there is no land ownership because the definition and enforcement of land ownership is one of the most ultimate functions of any government, since the creation of first city-states (e.g. ancient Babylon).
So if the government permits you to dig that hole in the first place, then what happens in an earthquake depends on local legislation. I don't really know how it works e.g. in the U.S. but I would assume that the boundary of your piece of land is defined in relation to physical markers that are recorded with their geocoordinates, but if the lay of the land changes so that the markers move, then the boundary of your plot will also move. And this could mean that the size of your plot changes.
Where I live, for instance, there are old boundary stones (which would in an earthquake naturally move along with the land on which they are laid) and newer marker bolts attached to bedrock that serve as reference points for geodesic measurement purposes. Also, there are height markers; for instance, when I started to build my house, the city would send a guy with equipment and start from one of these markers and then tell me if the foundations of the house are at right elevation. Should there be a major earthquake (not really a possibility here, ours is just about the most stable bedrock on Earth) then the changed positions (coordinates) would have to be recorded in land registry.