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Mount St. Helens volcano. Three-dimensional Landsat-5 satellite infrared (IR) image of the Mount Saint Helens Volcano looking south. In the background the Mount Hood volcano can be seen. Here, IR light, shortwave IR and green light are shown as green, red and blue respectively. This image is constructed from data obtained from Landsat's Thematic Mapper instrument. By a process known as digital elevation modelling, the image is made three-dimensional. In this case it is given a x2 vertical exaggeration. On 18th May 1980 Mount St. Helens erupted blowing off about 3 cubic kilo- metres of the volcano and leaving a post eruption crater. Mt St. Helens is in Washington State, USA. (KEYSTONE/SCIENCE PHOTO LIBRARY/NASA)