One of the most unusual national parks, Yellowstone, offers a complex and surprising geological history with its dramatic basalt plateaus, remarkable craters, and other worldly geysers. This captivating environment is the result of millions of years of geological changes from pressure and other forces happening deep below the earth’s surface.
Yellowstone National Park sits upon a large volcanic system and is one of the few known geological “hot spots” in North America. Hot spots are areas where the surface is connected to the boundary between the crust and the mantle below. The movement of the continental plates allow superheated magma direct access to the surface crust, ultimately causing a variety of geological phenomena. Yellowstone offers a one-of-a-kind experience that is hard to see because most activity similar to that which takes place in Yellowstone occurs deep within the oceans. The upward flow of energy from the area near the planet’s core is responsible for the geysers, basalt upthrusts, and craters in the area. As the plate Yellowstone sits upon moves northward, the land is scarred from the intense heat from below. But it’s these “scars” that make Yellowstone such a great place to visit.
Three major caldera eruptions were known to have occurred in Yellowstone National Park. A caldera is an immense basin formed when magma is quickly ejected from a cavity below ground and the land overlying the cavity collapses forming a sunken crater. Yellowstone’s main calderas were formed 2 million, 1.3 million, and about 630,000 years ago. The areas below the calderas may refill with magma causing excessive below ground heat which is the source for the hot springs, geysers, and steam vents seen within the national park.
Yellowstone National Park experiences many minor earthquakes on a daily basis. Less than a 3.0 on the Richter scale, most of these pass unnoticed by visitors; however they speak to the volatile past of Yellowstone. Historically, Yellowstone has been the location for large earthquakes as the continental plate continues its slow creep above the mantle. Most recently, on June 30, 1975, a magnitude 6.1 earthquake occurred west of Yellowstone Lake.
The area below Yellowstone has recently been termed a “super-volcano” and is considered to have potential for future geological events. Many magazines and entertainment shows have suggested the possibility of an eruption of enormous magnitude destroying much of the park. However, scientists and geologists have little support for this hypothesis. While geologists agree that there is potential for future earthquakes, caldera collapses, and possibly even volcanic eruptions within the park, these events will likely occur far into the future.
For more information about America’s national parks, visit www.nationalparks.org where you can learn more about how you can protect America’s national parks, home to approximately 400 endangered species, and download the free Owner’s Guide.