This high-resolution 3-D view, obtained in September 1994 by space shuttle astronauts, shows the summit crater and dacitic lava dome of Mount St. Helens. This once conical stratovolcano erupted on May 18, 1980. The summit crater, which opens to the north, is about 9 kilometers across and 1.6 kilometers deep and formed when the north flank collapsed in a massive avalanche. The crater has since been partially refilled by the extrusion of viscous lava domes. The dome seen here formed in October 1986 and was 1 kilometer wide and 280 meters high.
The irregular dark shape at the upper right is Spirit Lake. The avalanche that triggered the eruption also slid into Spirit Lake, displacing it to the north. The extensive gray areas to the north of the volcano were once heavily forested. These trees were destroyed or buried in the lateral blast of the eruption. Despite the magnitude of the 1980 eruption and the size of the area affected, it is dwarfed by some historical eruptions, such as those of Long Valley caldera (slide #11), California, and Cerro Galan, Argentina.
STS 64 images