They are the 28 most populated cities in that country. A study reveals that they are all sinking to a greater or lesser extent. Not only the coastal for the increase in sea level: also inside. The US cities are sinking. It is not a metaphor.
Some cities are sinking at different rhythms at different points, or sinking in some places and ascending in others. It could generate tensions that could affect buildings and other infrastructure. The massive and continuous extraction of groundwater is the most common cause of these earth movements. The study is published in the journal Nature Cities.
Heavy buildings
"As cities continue to grow, we will see how more cities expand towards sinking regions." The investigators affirmed in a statement. "It can generate tensions in the infrastructure that will exceed their security limit."
The rapid sinking of coastal metropolis such as Yakarta, Venice and New Orleans is already news. Many places on the east coast of the United States and other parts of the world are also. In 28 cities, two thirds or more of its surface is sinking. In total, around 34 million people live in affected areas.
The city that sinks more quickly is Houston. It has more than 40% of its surface sinking more than 5 millimeters per year. 12% sinks twice that speed. The extraction of groundwater for human use was the cause of 80% of the total sinking. Demographic growth and the use of water will aggravate the sinking in the future. The weight of buildings is another factor. The more than one million buildings in New York exert so much pressure that contribute to the continuous sinking of the city.
Unequal sinking
Some buildings in the Miami area are sinking. Partly due to alterations in the subsoil caused by the construction of new buildings in the vicinity. Much of New York City is sinking slowly, with some critical points. Especially around La Guardia airport, and parts of the Bay of Jamaica and Staten Island.
The US cities are sinking, but not at the same rate. Some areas sink while others rise. The elevation in certain areas of fact more than compensates the general sinking in three cities: Jacksonville, Florida; Memphis, Tennessee and San José, California.
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