i was thinking about this again today. and i realised that most, if not all the ideas i have come across seem to assume we will mark the spots once, and leave them for 10, 000 years. well if we do that, OF COURSE the markers will become obsolete. that's like asking for it. so why not mark the spots, and keep on updating the markers at regular intervals? say, every fifty or hundred years? that way, if new information about the waste (like its stability, how reactive it is etc) has been discovered, it can be added, and this also has the advantage of being able to have the markers evolve with changing cultures and societies, to make the warnings relevant and keep them that way... lets say, hypothetically, that we put a system in place to update/replace the markers every 50 yrs, then not only will the info on them remain relevant, the language and means of conveying the info will also remain relevant because it will change as society changes. theoretically if we could keep doing that for the next 10, 000 years, people will still be very much aware of the issue and thus be less likely to dig it up because they will know exactly what it is, and why it is dangerous, and will (hopefully) also have archives of historical evidence of it being there.