File:SIR-C-X-SAR Galapagos collage.jpg

English: (Top left: P-43914; top right: P-43913; bottom left: P-43938;

bottom right: P-43939) These four images show varying three-dimensional perspectives of Isla Isabela — one of the chain of Galapagos Islands located in the eastern Pacific Ocean about 1,200 kilometers (750 miles) off the western coast of Ecuador in South America. The views were constructed by overlaying radar images from SIR-C/X-SAR on digital elevation maps produced by TOPSAR, a prototype airborne interferometric radar that produces simultaneous image and elevation data. The SIR-C/X-SAR images were obtained on April 10, 1994, during the 24th orbit of the space shuttle Endeavour (STS-59). Vertical exaggeration, about 1.87 times the actual relief, is used by scientists to detect relationships between structure (faults and fractures) and topography.

The Isla Isabela images are centered at about 0.5 degree south latitude and 91 degrees west longitude and cover an area of 75 by 60 kilometers (47 by 37 miles). The Galapagos Islands have six active volcanoes — similar to the volcanoes found in the Hawaiian Islands — and reflect the volcanic processes that occur where the ocean floor is created. The images show varying views of Alcedo (top left and right); Wolf, Darwin, and Alcedo (bottom left, from back); and Wolf and Darwin (bottom right, from back).

Since Charles Darwin's visit to the area in 1835, there have been more than 60 recorded eruptions on the Galapagos volcanoes. The images show the rougher lava flows as bright features, while ash deposits and smooth pahoehoe lava flows appear dark.