Geothermal areas of Yellowstone#West Thumb Geyser Basin

The West Thumb Geyser Basin is the largest geyser basin on the shores of Yellowstone Lake in Yellowstone National Park. Go to West Thumb Geyser Basin and the Potts Basin is one of the north.

The heat source of the hydrothermal properties of this area is about 3000 m depth with relatively close to the earth's surface. The basin was formed by an eruption of the Yellowstone volcano approximately 125000-200000 years ago. Later, the resulting caldera filled with water and so extended the Yellowstone Lake from. The West Thumb Basin is about the size of Crater Lake in Oregon, but much smaller than the Yellowstone Caldera, which was created when volcanic eruption 600,000 years ago at the same place. It is thus a caldera in a larger caldera.

When aufwölbte the underground magma chamber formed annular cracks, which could escape the magma. Until today it is the heat source for the West Thumb Geyser Basin.

The hydrothermal properties of this region are not only found on the lake shore, but spread out under the lake. In the 1990s, several underwater geysers were discovered. They can be recognized as the holes in the ice melted in summer and low warpage in the water, and in the winter. On average, the ice of Yellowstone Lake in winter is about 10 cm thick.