Figures and pictures used with permission from
"Windows into the Earth, The Geologic Story of
Yellowstone and Grand Teton National Park", Robert B.
Smith and Lee J. Siegel, Oxford University Press,
2000.
Figure 3. Areas of the United
States that once were covered by volcanic ash from
Yellowstone's giant eruptions 2 million and 630,000 years
ago, compared with ashfall from the 760,000-year-old Long
Valley caldera eruptions at Mammoth Lakes, California, and
the 1980 eruption of Mount St. Helens, Washington. (Adapted
from Sarna-Wojcicki, 1991.)
