Mount St. Helens is an active stratovolcano in Skamania County, Washington, in the Pacific Northwest region of the United States. It is located 96 miles (154 km) south of Seattle and 53 miles (85 km) northeast of Portland, Oregon. The mountain is part of the Cascade Range and was initially known as Louwala-Clough which means 'smoking or fire mountain' in the language of the Klickitats. It was named for British diplomat Lord St Helens who was a friend of George Vancouver who made a survey of the area in the late 18th century.
It is most famous for a catastrophic eruption on May 18, 1980. That eruption was the most deadly and economically destructive volcanic eruption in the history of the United States. Fifty-seven people were killed and 200 homes, 47 bridges, 15 miles (24 km) of railways and 185 miles (300 km) of highway were destroyed. The eruption blew off the top of the mountain, reducing its summit from 9,677 feet (2,950 m) to 8,364 feet (2,550 m) in elevation and replacing it with a mile-wide (1.5 km-wide) horseshoe-shaped crater.
Like most other volcanoes in the Cascade Range, St. Helens is a great cone of rubble consisting of lava rock interlayered with ash, pumice and other deposits. Volcanic cones of this internal structure are called composite cones or stratovolcanoes. Mount St. Helens includes layers of basalt and andesite through which several domes of dacite lava have erupted. The largest of the dacite domes formed the previous summit; another formed Goat Rocks dome on the northern flank. These were destroyed in St. Helens' 1980 eruption.
README.TXT:
This highly flexible terrain model includes a variable resolution elevation object, based on 10 Meter Digital Elevation Model data and five very detailed textures.
You can adjust the grid density of the elevation object in 3DS Max to suit your needs. We recommend no denser a grid than 5 meter, as further subdivision won't yield better topographical fidelity. When you load the file initially, the grid is set to 50 meters, to speed loading on slower machines. Select the TerrainModel Object, then the Elevation in the modifier stack and adjust the grid density to suit your needs. The .3DS and .DXF formats do not support the elevation object, and so are saved with a 5 meter grid.
The textures are USGS Topographical, USGS 1 Meter Greyscale, NASA Landsat 7 Visible and a high resolution (~1 M) Color Texture of the mountain itself. The high detail color does not cover the entire topography like the other three textures, but allows you to zoom in quite tightly and still have a good looking mountain. The unmapped area is white, allowing you to overlay the high detail onto a generic background, or over one of the lower resolution textures provided, depending on your needs. The Color Composite texture is the high-resolution data over the Landsat 7 background, with the background color adjusted to closely match the detail. Some seams are visible in the composite, due to the different year of data acquisition. Most notable on Spirit lake where the log-jam has moved.
Be sure to download the textures you need in the attached file section. They are packaged separately to keep the download sizes reasonable.
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