In general, where on earth are the subduction zones located?

In general, they are on the edges of continents, where you find mountain ranges, regular earthquakes and active volcanoes - Eg: South America and Asia.

Subduction zones are where tectonic plates collide, with a plate plunging beneath the other.
Sometimes these collisions are gradual but often they occur in large movements that can cause concussions.
  As the subduction zones are generally on seabeds, earthquakes can trigger tsunamis in these areas.

Europe may be starting to dive under Africa, creating a new subduction zone and potentially increasing the risk of earthquakes in the western Mediterranean Sea.

Humans have survived and thrived in mexico city by using technology to create greater access to land. when the spanish conquered the aztec capital, tenochtitlan, in the 16th century, they built mexico city by draining the lakes and filling in the lake water to create more arable land for agriculture. this technique of land reclamation has continued to be fundamental to human civilization in mexico city. 

Physical systems is the answer