Speaking of inclined buildings, the first thing people think of is often the Leaning Tower of Pisa in Italy. But there is such a city,
Like some coastal cities, Mexico City is also experiencing land subsidence problems.
So why did the capital of Mexico sink so much,
Mexico City is located in central Mexico, at the same latitude as the Sahara Desert.
Therefore, humans lived in Mexico City for a long time. The most famous Aztecs among Native Americans live here.
The early aborigines built a city on a small island on Lake Tescoco, the largest in the area at the time. It was a unique lake capital until European colonists came to this continent. It was the Spanish who conquered Mexico,
During the war, the island city on Lake Tescoco was razed to the ground. Then the Spaniards built a new city on this land,
With the development of New Spain,
After the 16th century, the Spaniards filled most of the lake for urban land use. Streets and squares replaced embankments and canals. The lake was gradually drained in the process of filling and blocking. Today we have
Although this has absorbed a huge number of people entering the city, it has many harms and brings many hidden dangers to the safety of urban residents. The first is the flood disaster. After the lake is drained,
Another hidden danger is more serious,
Volcanic soil has a characteristic-porous. Rainwater will pass through the porous soil directly into the underground aquifer,
The underground structure of Mexico City can be imagined as a sponge. When water is poured into the sponge, it will absorb water and expand.
So if there is a problem with the water cycle in Mexico City and the amount of water in the underground aquifer is not enough to support the soil and buildings on the ground, the entire city will sink.
The danger does not directly come from the sinking of the city. If the whole city moves downward at the same speed, nothing will happen.
Although the underground structure of Mexico City is so unstable, as long as the aquifer has enough water, it can support an increasingly busy city on the ground. A city built on the lake bed
Most areas of Mexico have a savanna climate. The whole year is divided into two seasons: dry and rainy, and precipitation mostly occurs in the rainy season. The extreme climate phenomenon caused by global warming makes the rainy season in Mexico become more and more violent.
This leads to the loss of excess precipitation in the rainy season before it penetrates into the aquifer, and insufficient precipitation to supplement groundwater in the dry season. Mexico’s
Simultaneously with the declining groundwater level, the population is gradually rising.
At the beginning of the 20th century, the population of Mexico was only about 14 million. Today, the population of Mexico City alone exceeds 22 million. Like other countries in Latin America, thousands of immigrants have poured into the capital from all over the country looking for opportunities to make this city from 1950
The city spread across the valley, almost erasing all remaining traces of the original lake.
The population of the Mexico City metropolitan area now ranks among the top in the world, and the narrow and limited land is difficult to carry the operation of the huge capital.
Tokyo is located in a subtropical monsoon climate zone and is also on the coast of an island country with abundant rainfall. Even with such superior congenital conditions, it once caused ground subsidence due to the excessive exploitation of groundwater, which reached its peak in 1968.
But Mexico City obviously cannot stop pumping groundwater.
In fact, when it comes to the water pipes in Mexico City, the locals are very proud.
The energy required to extract and transport these water resources is huge, and what is even more heartbreaking is this
This forms a vicious circle: water is taken from deep underground due to lack of water, and the water taken out is due to ground subsidence.
The Mexican city government has invested a lot of money in order to ensure the city’s water supply, but urban residents’ water has not been effectively guaranteed.
Due to pollution, the tap water cannot be drunk directly, and more people choose to raise funds to rent trucks to transport drinking water. In Mexico City, about 500 vehicles travel between the suburbs and urban areas every day
The entire Mexico City sank 9 meters in the last century, and the first 20 years of this century
Uncontrollable ground subsidence put the building in danger,
The most obvious evidence is the Independence Monument, the symbol of Mexico's founding.
It stands in the center of the turntable of the open boulevard in the city center. The gilded angel on the top of the building looks down on the traffic underneath. She is the pride of Mexicans.
When the Mexican President cut the ribbon for it in 1910, the monument base only had
Nowadays, land subsidence has threatened the life and property safety of Mexican urban residents.
But the population of Mexico City is currently increasing by 350,000 per year. According to Alan Morgan, a geologist at the University of Waterloo, the groundwater level in the surrounding area of the capital drops by about 3 feet every year, because the precipitation rate is lower than the evaporation rate.
The entire city's building foundations, wells, streets and sewer systems will be damaged to varying degrees, and the city may also be paralyzed.
The only "benefits" it brings may be the creation of a number of jobs-now Mexico City has a dedicated team of workers
When building cities on small islands in the lake, perhaps even the best prophet of Aztec would not have thought of it,
Central American cyberpunk, you can see the whole picture here.