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The Large Salt Desert

Credits
USGS/EROS; Link: http://earthexplorer.usgs.gov/

The salt desert Dasht-e Kavir is located in Iran in the east of the Zagros Mountains. Being the largest Iranian desert, it is a gigantic salt pan whose crusts of salt protect the ground against total dehydration. On the left-hand side of the picture, you can see one of the few streets crossing the largely uninhabited wasteland.

 

Location: Iran
Picture taken on May 10, 2003
Sensor: Landsat 7 ETM+

Lethal Poison on the Coast of Namibia

Credits
NASA/GSFC, Link: http://rapidfire.sci.gsfc.nasa.gov

This satellite image shows a turquoise hydrogen sulphide cloud offshore Namibia. This cloud developed under oxygen-deficient conditions at the bottom of the sea as a result of the micro bacterial decomposition of organic material. Hydrogen sulphide is lethal when eaten by fishes and other marine creatures, constituting a serious problem for the fishers. Above the turquoise cloud, you can see billows of sand that are being blown from the Namib Desert onto the open sea.

 

Location: Namibia
Picture taken on June 17, 2010
Sensor: Terra MODIS

The Growing City of Las Vegas

Credits
USGS; Link: http://earthexplorer.usgs.gov/

In comparing these two images, you get an idea of the rapid growth of Las Vegas, Nevada, between 1973 and 2002. Las Vegas is one of the fastest-growing US cities. Its high immigration rate and its areal extent have a negative effect on the water budget of this arid region. In order to solve this problem, politicians intervened: It is now forbidden to build new swimming pools, fountains must be operated using wastewater and the lawn can only be watered at certain days of the week.

 

Salt Lake in Australia

Credits
NASA (Jesse Allen, Robert Simmon); USGS; Link: http://earthobservatory.nasa.gov

In Central Australia, a large area of “ephemeral lakes” stretches across the borders of several states. Due to an average precipitation of 149 to 216 millimetres p.a., the lake basins are only occasionally filled with water and remain dry-as-dust salines most of the year. This image shows the easternmost periphery of Lake Frome in South Australia. When the picture was taken, Lake Frome was a dry salt lake filled with white sediment. The surface of the lake is uneven and characterised by drop-shaped hills.

 

Richat Structure, Mauretania

Credits
USGS; Link: http://www.usgs.gov

Since the first space missions, the circular “Richat Structure” in the northwest of Africa has ranked among the most striking points of orientation for astronauts. The “Eye of the Sahara” is 45 km in diameter and was initially interpreted as the result of a meteorite impact. Meanwhile, it is assumed to be a circular uplift of several layers of earth. Rocks of different solidness had been eroding to a greater or lesser extent over time, which led to the distinct looks of the “Richat Structure” as we know it today.