Yellowstone National Park

Yellowstone National Park is a U.S. National Park located in the western states of Wyoming, Montana, and Idaho. Yellowstone is the first national park established in the world and covers 3,472 square miles (8,987 kmē), mostly in the northwest corner of Wyoming. The park is famous for its various geysers, hot springs, super volcano and other geothermal features and is home to grizzly bears, wolves, and free-ranging herds of bison and elk. It is the core of the Greater Yellowstone Ecosystem, one of the largest intact temperate zone ecosystems remaining on the planet. The world's most famous geyser, the Old Faithful Geyser, is also located in Yellowstone National Park.

Approximately 96 percent of the land area of Yellowstone National Park is located in the state of Wyoming. Another 3 percent is in Montana and the remaining 1 percent is in Idaho. The park is 63 miles (102 km) north to south and 54 miles (87 km) west to east by air. At 2,219,789 acres (898,317 ha), the park is larger than the states of Rhode Island and Delaware combined. Rivers and lakes cover 5 percent of the land area, with the largest waterbody being Yellowstone Lake which covers 87,040 acres (35,400 ha). Yellowstone Lake is up to 400 feet (122 m) deep and has 110 miles (177 km) of shoreline. Sitting at an elevation of 7,733 feet (2,357 m) above sea level, Yellowstone Lake is the largest high altitude lake in North America. 80 percent of the land area of the park is covered by forest and most of the rest is grassland.

Yellowstone has frequent earthquakes, but virtually all of them are undetectable to people. However, there are thousands of small earthquakes every year, including six that have been at least magnitude 6 or greater in historical times. In 1959, a 7.5 magnitude quake struck just outside the northwest boundary of the park. This quake triggered a huge landslide, which caused a partial dam collapse on Hebgen Lake, and immediately downstream, the sediment from the landslide dammed the river and created another lake, known as earthquake lake. 28 people were killed and property damage was extensive in the immediate region. The quake caused some geysers in the northwestern section of the park to erupt, large cracks in the ground formed and emitted steam, and some hot springs normally clear water turned muddy. A 6.1 magnitude quake struck inside the park on June 30, 1975, but damage was minimal. For three months in 1985, 3,000 minor earthquakes were detected in the northwestern section of the park, during what has been referred to as an earthquake swarm, and has been attributed to minor subsidence of the Yellowstone caldera.