Why Were Great Cities Built in Quake Zone?

The seats of ancient civilizations were great meeting places. Trade routes, ideas, and cultural currents converged there—as did tectonic plates, says archaeological geologist Eric R. Force of the University of Arizona in Tucson.

On a map of the Eastern Hemisphere, Force overlaid the locations of plate boundaries and the founding cities of thirteen ancient civilizations. He discovered that eleven of the thirteen fell within 120 miles of the Eurasian plate's southern boundary—too many, and too close, to be just coincidence.

The great plates of the Earth's crust collide at tectonic boundaries, which often feature active volcanoes, earthquakes, and large water springs, and which parallel seacoasts for long stretches. Some of those features would seem to obstruct cultural advancement, others to help; whether any, alone or in combination, can explain why civilizations tend to arise near tectonic boundaries remains subject to speculation.

Force points out one intriguing possibility: that frequent shake-ups by earthquakes, tsunamis, or other natural disasters destroy the old, making way for improved infrastructure and new customs.

The seats of civilizations that sprang from older civilizations hugged tectonic lines more closely than the seats of self-generating societies, he found. Similarly, the farther a civilization was from a boundary, the longer it endured.

The findings were detailed in the journal Geoarchaeology.