s volcanic caldera. Fed by intermittent rivers and springs, the lake contains high concentrations of lithium, potassium, and boron. These three images show how Landsat 8’s extended spectral capabilities can be used to highlight various surface features, often with vibrant results.
The left image uses the three visible bands from Landsat (red, green, and blue) to create a natural color representation. In this image, the ground features appear in colors very similar to what would be seen by the human eye. Non-vegetated ground is brown, and water appears dark. The bright areas indicate salt and other evaporated deposits in dry or very shallow areas of the lake.
Along with the visible wavelengths, Landsat 8’s extended spectral bands show additional details that cannot be seen by the human eye. The middle image uses two infrared bands that can be used to highlight the water bodies (red), salt and evaporated deposits (yellow, gold), and varying composition of other materials (green, tan) within the basin. The right image also uses infrared bands, but in a different combination which accentuates the salt and evaporated deposits (light blue) and the geologic features within the surrounding volcanic region (brown, green).
The many spectral bands available on Landsat provide an important set of tools for scientists, geologists, and others to study and map features on the Earth’s landscape. These features cannot always be seen by the human eye alone.
Near the western edge of the Sahara Desert is a feature that resembles a large eye when viewed from space. The Eye of the Sahara, also known as the Richat Structure or Guelb er Richat, is a symmetrical dome of eroded sedimentary and volcanic rock. The outermost rings measure approximately 40 km (25 miles) across. Persistent northeasterly winds keep much of the dome free from sand, exposing the various layers of rock. The circular feature was initially interpreted to be an asteroid impact structure, but most scientists have now concluded that it was caused by geologic uplift.
This Landsat mosaic of four different scenes shows the geologic feature in false color. By blending visible and infrared wavelengths (bands), scientists can enhance the visibility of the various rock layers in contrast to the surrounding sand (yellow to white).
The largest mud volcano in the world is located in Porong, Sidoarjo in Indonesia, where it is locally called the Lusi Mud Volcano. Mud volcanoes are created when hot mud (rather than lava) erupts from a vent on the Earth’s surface. This type of eruption typically includes a mixture of steam and gas, groundwater, and mud-based slurry.
Lusi first erupted in May 2006, and is expected to continue erupting for decades. So far, enough mud has erupted to cover nearly 27,000 football fields in a meter of mud. These two Landsat images were acquired by Landsat 7 on April 28, 2006 (left) and June 24, 2015 (right). The round feature in the center of the right-hand image shows the current extent of the mudflow. This second image also shows a series of levee structures that were built in 2008 to surround and contain the ongoing mudflows.
The Landsat sensors include numerous spectral bands that can be used in various combinations, allowing users to accentuate and study specific features on the Earth’s surface. These two images used a combination of shortwave and near-infrared wavelengths to highlight the mudflow area, in contrast to the surrounding urban and agricultural areas.
The afternoon of Sunday June 14, Alaskan authorities were notified of a 40-acre fire in Willow, AK. Named the Sockeye Fire for the street where the fire began, the fire moved quickly through the black spruce forested area due to flat topography and hot, dry, windy weather. In only 48 hours, the burned area grew to about 6,500–7,000 acres. Strong north winds are expected to drive the fires to the south, threatening populated areas. Smoke could affect Anchorage, 80 miles to the south.
These two Landsat images were acquired by Landsat 8 on May 30, 2015 (left) and June 15, 2015 (right). Bright red indic