rveys. The 30-meter resolution of Landsat provides enough detail for remote sensing scientists to observe and quantify such changes.
Lithium Mining in Salar de Atacama, Chile January 19, 2016
The Salar de Atacama in Chile is a large, dry salt flat surrounded by mountain ranges and is one of the driest places on Earth. Parts of the Atacama Desert have gone without rain for as long as people have been keeping track, but water rich in dissolved salts lies beneath this flat surface. The Salar is particularly rich in lithium salts.
Lithium is used in rechargeable batteries. With increased use of smartphones, mobile computers, and electric cars, there is higher demand for the soft, silvery metal.
Brines from beneath the salty crust are pumped to evaporation ponds, visible as the blue rectangles in these Landsat images. The extremely dry and windy conditions here result in an efficient process. The concentrated salts are left behind after evaporation from which lithium carbonate and other materials can be extracted.
The lithium mining activities in the Salar de Atacama have expanded over the years, as can be seen in these Landsat images acquired in 1993 and 2015. Landsat imagery can help study worldwide land change effects from a variety of mining types.
New Year’s Flooding in the Midwest January 6, 2016
At the end of 2015, a series of storms dropped 6–10 inches of rain in a few days over the central part of the United States. Missouri and Illinois were particularly hard hit, with many waterways overflowing their banks.
Water has receded in most places, but a Landsat 7 image acquired January 1, 2016, clearly shows an example of the extent of the flooding. Flowing north to south at the top center of the image is the Wabash River, which forms the border between Illinois and Indiana. The Wabash flows into the Ohio River.
Water is blue in these images. The December 8, 2015, image shows the rivers at normal water levels. The January 1 image shows the swollen Wabash and Ohio Rivers, each of them submerging the floodplains. Smaller tributaries have also overflowed their banks.
USGS collects streamflow data at streamgages throughout the region, and throughout the United States. These gages measure water levels, streamflow, and rainfall. Along with satellite images, these data help monitor the flooding, and help project the severity of flooding effects downstream.
The Selenga River begins in Mongolia and flows north into Russia where it empties into Lake Baikal, the world’s deepest lake. The river slows as it approaches the lake, dropping large amounts of sediment in a wide alluvial plain. The braided river flows past farm fields—the blocky shapes in the images—and to the lake.
The river forms a unique delta as it carries sediment to Lake Baikal. These Landsat images show the delta in 1989 and 2015. While the overall shape of the delta has not changed significantly, a halo of sand bars surrounds the edge of the delta in the 2015 image. Varying lake levels and the river’s sediment load influence the changing shape of the delta and its sand bars.
Landsat data are freely available to anyone interested in researching and monitoring changes happening to the Earth’s surface.
Brazilian Mining Disaster, Doce River December 16, 2015
On November 5, 2015, a tailings pond dam failed at an iron mine in southeastern Brazil, sending contaminated water sediment through the nearby village of Bento Rodrigues and into tributaries of the Rio Doce (Sweet River). (See http://eros.usgs.gov/imagegallery/image-week-2#Brazil_Images) The sediment from that disaster has since moved downstream to the mouth of the Doce River.
The Landsat 8 image from September 11, 2015, shows what the mouth of the Doce River looks like under normal conditions. A Landsat 8 image acquired on November 30 shows a plume of sediment flowing into the Atlantic Ocean. This may be contaminated sediment from the dam breach. Advanced Landsat 8 capabilities, including the new coastal aerosol band and superior instrument performance, may improve monitoring the extent of sediment flow in the river