NASA drone observations have shown that New Orleans goes underground and water at an extremely uneven speed - some areas of the city "sink" at a speed of 5 centimeters per year, while others - only 3.5-4 centimeters, according to an article published in the magazine JGR: Solid Earth.
“The authorities can use this data to improve the effectiveness of measures to slow down and prevent this process, which should help New Orleans and its associated coastline continue to exist. In addition, the data we collect will enable us to better predict the areas that will be hit hardest by floods, helping us save more lives,”said Cathleen Jones of NASA's Jet Propulsion Laboratory in Pasadena, USA.
Today, many coastal cities in North America and Europe, including Washington and New York, are at risk of flooding due to a special geological phenomenon - the so-called subsidence of rocks. Such "immersions" can occur for a variety of reasons - this can be the fault of both a person pumping water from artesian wells, and various geological processes caused by the melting of glaciers in the distant past and other things not related to people.
As Jones says, something similar has been happening around New Orleans and the entire southern coast of the United States for tens of thousands of years as a result of rising sea levels caused by the melting of the polar ice cap. In the Mississippi Delta region, this sinking into the ground was offset by deposits of silt, sand and other rocks that fell onto land during river floods and floods.
The construction of dams, dams and other river structures changed the picture for the worse - now nothing prevents the subsidence of the soil under New Orleans and other settlements in the Mississippi Delta. Experts from NASA decided to calculate the speed with which this dive is going, and tried to reveal the inner background of this process.
To do this, geologists from the Jet Propulsion Laboratory used special radars installed on board UAVSAR drones. These devices, according to their creators, are able to "see" differences in the height of the surface in fractions of a centimeter, which allowed scientists to accurately measure how quickly not only certain areas of New Orleans sank underground, but also houses and even parts of houses, combining images from 2009- 2012 years.
As it turned out, the city is submerged under water and the ground is extremely uneven - in some areas the rate of fall in height is 5 centimeters per year, while in others it is almost half. Such differences, according to scientists, suggest that not only geological processes, but also people are to blame for the immersion of New Orleans.
The main "contribution" of man to this process consists in two things - in draining and discharging water from some marshy regions of the area, as well as in the construction of artesian wells and pumping water from the ground. All this, according to experts from NASA, accelerates the process of subsidence of rocks and makes the coastline of Louisiana vulnerable to natural forces, as demonstrated in 2005 by Hurricane Katrina.
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