Will we have a new Atlantis? Hopefully not, but looking at what has been happening in recent years, the phenomenon begins to worry. A city with a population of nearly 9 millions, covering a metropolitan area of over 20 million inhabitants is sinking.
The METROPOLIS that is SINKING: 2 meters in the last 4 years
It is one of the most densly populated cities in America, Mexico City, and, in the last 4 years, the land on which it is built has been yielding and sinking about 2 meters.
# The ground sinks 50 centimeters per year
The phenomenon that is causing Mexico City to sink is called subsidence: a geological process that causes a progressive and gradual collapse of the ground. Usually, the main reasons are natural events, for instance earthquakes, or human activities such as water and mining extraction. However, what is surprising is that the land on which Mexico City is built is sinking at the tremendous speed of about 50 centimeters a year and there are no signs of improvement.
So, why is Mexico City sinking? The metropolis was originally built on what was the salt lake of Texcoco, on a clay soil. This caused the ground to gradually aggregate and compact, thus damaging houses, buildings and infrastructure and eventually leading them to sink.
Worrying news: the collapse of the soil will affect 19% of the world population
Cities are sinking
A group of researchers has recently studied the phenomenon of subsidence on a global scale and they discovered that, by 2040, about 1.2 billion people, accounting for 21% of the global GDP, shall witness soil subsidence in their cities. It is estimated that Asia will be the continent at the highest risk because subsidence might involve a large slice of soil, affecting 86% of the population. In addition, the problem will be the rate at which the ground will yield: up to 28 centimeters per year.
However, it seems that, for example as far as Italy is concerned, there can be no such drastic, or at least not immediate, subsidence, since this phenomenon is never so extreme except in small, marginal areas.
BEATRICE BARAZZETTI
