![]() Three visualization methods were combined to produce this image: shading of topographic slopes, color coding of topographic height, and then projection into a perspective view. Predicting such eruptions still presents challenges, but migration of magma within these volcanoes often produces distinctive seismic activity and minor but measurable topographic changes that can give warning of a potential eruption. Eruptions at Mount Saint Helens subsided in 1986, but renewed volcanic activity here and at other Cascade volcanoes is inevitable. ![]() Subsequent eruptions built a volcanic dome within the crater, and the high rainfall of this area lead to substantial erosion of the poorly consolidated landslide material. However, the explosive eruption of May 18, 1980, caused the upper 400 meters (1300 feet) of the mountain to collapse, slide, and spread northward, covering much of the adjacent terrain (lower left), leaving a crater atop the greatly shortened mountain. Prior to 1980, Mount Saint Helens had a shape roughly similar to other Cascade peaks, a tall, bold, irregular conic form that rose to 2950 meters (9677 feet). Mount Adams (left background) and Mount Hood (right background) are also seen in this view, which was created entirely from elevation data produced by the Shuttle Radar Topography Mission. ![]() The mountain is one of several prominent volcanoes of the Cascade Range that stretches from British Columbia, Canada, southward through Washington, Oregon, and into northern California. Mount Saint Helens is a prime example of how Earth's topographic form can greatly change even within our lifetimes. Mount Saint Helens, Washington, USA, SRTM Perspective: Shaded Relief and Colored Height ![]()
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