2 upvotes, 2 direct replies (showing 2)
View submission: Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science
Fair enough. Then why ancient cities are under ground? Where did all this ground come from?
Edit: spelling
Comment by CrustalTrudger at 13/09/2023 at 15:24 UTC
8 upvotes, 0 direct replies
This is addressed in one of our FAQs[1].
1: https://www.reddit.com/r/askscience/wiki/planetary_sciences/artifacts_buried/
Comment by atomfullerene at 13/09/2023 at 16:15 UTC
6 upvotes, 0 direct replies
Reasons things are under the ground:
1. buildings that get buried survive. Buildings in places where the ground erodes out from under them don't stick around to be seen in the modern day
2. People love to live near water. That often means building on floodplains and in other depositional environments....aka, the places where sediment that washes down from the mountains builds up. This tends to bury old buildings
3. People build on top of things, burying them. Prior to the invention of trucks and earthmoving equipment, it was a pain to haul away rubble. People would just knock down old buildings, level out the rubble, and build on top of them. And of course people would bring all sorts of stuff into cities, throw it out, and it would accumulate over time. Especially in very old cities in climates where buildings were made of mud-brick, cities build up into mounds just from the accumulated remains of buildings built on top of each other.
4. Several cities raised their "street level" to avoid flooding issues and install sewers and pipework. Chicago is probably the most famous example of this, but other cities heavily modified their terrain as well.