There are sf stories about trying to send warnings to the far future. As difficult as it is to preserve the information, it’s even harder to make later generations pay attention to it.
People have been trying to solve this problem for a long time. The poem “Ozymandias” mocks those who did it for selfish purposes. But what if you’re trying to save your children’s children? Consider the tsunami warnings on these 600-year-old Japanese tablets:
Modern sea walls failed to protect coastal towns from Japan’s destructive tsunami last month. But in the hamlet of Aneyoshi, a single centuries-old tablet saved the day.
“High dwellings are the peace and harmony of our descendants,” the stone slab reads.
“Remember the calamity of the great tsunamis. Do not build any homes below this point.”
It was advice the dozen or so households of Aneyoshi heeded, and their homes emerged unscathed from a disaster that flattened low-lying communities elsewhere and killed thousands along Japan’s northeastern shore.
Hundreds of such markers dot the coastline, some more than 600 years old. Collectively they form a crude warning system for Japan, whose long coasts along major fault lines have made it a repeated target of earthquakes and tsunamis over the centuries.