Detroit is about 300 years old and it's lost over 60% of its peak 1950s population as sane people continue to flee from it. Destroying a city doesn't always require a natural disaster. Humans can do a great job of it on their own.
Detroit started to bleed in the 1960s, after the late 1950s auto industry peak (first 10 million vehicle year, and the last one for a long while), followed by the riots, white flight, and the disaster that was Coleman Young.
Cahokia got flooded out, and the flood killed the crops in the field. It never recovered.