Why do human populations concentrate near fault lines, volcanoes, etc.?

Question

I've noticed that many places with large populations tend to be prime zones for natural disaster.

Examples: Silicon Valley = earthquakes, Houston = hurricanes and floods, Japan = tsunamis and earthquakes, Santa Maria = volcano, Vesuvius = volcano, etc.

This doesn't seem like a coincidence, especially given that people would naturally want to stay away from disaster-prone sites. Clearly there must be a benefit to living in such places.

My guess has always been that it probably goes something like this:

Active fault zone → mountains & volcanoes → rain & water → fertile soil & wildlife → food

Or maybe like this:

Storms/monsoons → rain & water → fertile soil & wildlife → food

But I really have no idea, and this has been a question I've had for a long time.

Is this accurate? Is there more than meets the eye? Is it maybe partly a coincidence?
Explanations would be greatly appreciated, since all I have right now is just a guess.

Answer 1

You're asking

Why do human populations concentrate near fault lines, volcanoes, etc.?

But the real question is

Do human populations concentrate near fault lines, volcanoes, etc.?

And the answer is not necessarily positive. Let's look at where earthquakes are:

and active volcanism:

Both maps are from Volcano Discovery. Here's a population density map:

Couldn't find the source for that, but a similar interactive website is this one: http://luminocity3d.org/WorldPopDen/

Finding a 1:1 correlation between these two natural hazards and population density is very hard. Most of the World's population reside in India, China, Europe, central Africa, and east North America. All of these areas not particularly hazardous in terms of fault lines and volcanoes. Other volcano-abundant areas are only populated if they're around the tropics (Mexico, Indonesia).

So no, the answer is that human population do not concentrate near fault lines or volcanoes more than they concentrate elsewhere.

On a local scale, however, volcanic soils are fertile and an excellent place to grow food. This might attract people to volcanoes, because food is vital for life and a maybe-yes-maybe-no threat of a volcano (particularly if it's not obviously active) is a lower priority thing for most people. Also see the interesting story of Pinatubo.

Sometimes, people did not know there was a hazard. Parícutin is a volcano in Mexico that just appeared out of nowhere in 1943. Christchurch, NZ, was considered a low earthquake risk zone until it was struck by several quakes in the recent years.

There is some truth to your two guesses that storms provide water for food and mountains lead to rivers which also provide water for food. But it's not a direct relationship. Think of the Nile river, which gets the water from mountains far south but feeds millions in Egypt. There are many more other examples.