th its 40-plus years of consistent imagery, the Landsat archive is perfect for studying the landscape changes caused by natural disasters and the gradual recovery process.
Haruj is the large volcanic field that dominates this Landsat image mosaic acquired over central Libya. The plateau was built from basaltic lava flows that erupted over time from approximately 150 separate volcanoes. The volcanic craters and lava flows are all evidence of a previous active period, well preserved in the dry Sahara Desert.
The geologic evolution of this landscape is not fully understood, but some scientists have used the texture and color differences revealed in satellite images to try to interpret the relative ages and sequence of different volcanic events. The numerous spectral bands and band combinations available from Landsat mean that the color variation of individual lava flows can be especially helpful for interpreting different phases of volcanic activity.
Many of the bright spots within the darker colored basalt flows are sand-filled craters associated with individual volcanoes. Other light-colored areas are depressions covered with silt and fine sand.
This image mosaic consists of numerous Landsat 8 scenes acquired in early 2015. Landsat images can be useful to support geologic mapping and studies of large and remote features such as this.
Lake Urmia, located in northwestern Iran, was once one of the largest saltwater lakes in the Middle East. It supports an important seasonal habitat for many species of migrating birds.
In recent years, the lake has diminished dramatically. Water enters Lake Urmia primarily from rainfall and inflowing rivers. The diversion of water from local rivers for agricultural use is one likely cause of Lake Urmia’s decline. Since 1996, drought has further contributed to the lower lake levels. The lake now covers about 10 percent of the area it covered in the 1970s.
These Landsat images show the changes to Lake Urmia’s surface area over the past fourteen years. Each image was created by mosaicking several individual Landsat scenes to show the full lake area. From 2000 to 2010, some changes can be seen. In the final image (2014), the entire southern portion of the salty lakebed is now exposed.
Future Landsat imagery will continue to be a useful tool for mapping and monitoring of further changes to Lake Urmia and its surrounding areas.
These two Landsat images show the urban area around Cape Town, South Africa. The more recent image (right) reveals scars from several fires that broke out in early March 2015, and were intensified by strong winds and hot summer temperatures.
The dark fire scar on the left side of the March 11 image is from a fire that had started ten days earlier and burned more than 5,000 hectares (12,000 acres). The dark scar on the right side of the same image is from the Jonkershoek Fire, which started March 9 and was still active at the time this image was collected. About 4,000 hectares (10,000 acres) were burned before this second fire was contained.
Landsat imagery is a valuable tool for the mapping and measurement of burned extent and lost vegetation due to wildfires. As the landscape begins to recover, Landsat will also be useful for monitoring the area’s regrowth and restoration.
Agricultural Land Use along the Chira River, Peru March 20, 2015
These two Landsat images show the expansion of agricultural fields along the Chira River in northern Peru. The green of irrigated fields contrasts against the arid background of the land in this coastal region. The main crops in this region include rice, cotton, maize, mangoes, and lemons.
The new agricultural areas in the second image (2014) are supported by irrigation from the Chira River and Poechos Reservoir in the upper right portion of the images. The reservoir and its system of dams were developed to generate electricity, control flooding, and support local irrigation needs.
Landsat imagery is often used to monitor the status and changes of agricultural land use and water resources over time.
New Land Forming in the Atchafalaya Basin 