The Yellowstone and Grand Teton region is one of the most dynamic seismic areas in the world -- wracked by earthquakes, cracked by water boiling to the surface, and littered with the detritus of previous volcanic eruptions. Today, the bowels of the Yellowstone caldera are again filling with magma. Geologic studies show that, for the past 2 million years, the plateau has blown its top every 600,000 years or so -- and the last explosion was about 600,000 years ago. That means that a titanic blow -- bigger than anything seen in recorded history -- could happen, well, any century now, give or take thousands of years. The geological time frame is a long one, by human standards, but this didn't stop people from getting excited when an unprecedented "swarm" of minor earthquakes rattled the park in early 2009. The good news is that the big one is not imminent; geologists say things need to heat up considerably first.
By the end of the 1872 Hayden expedition, explorers had identified several distinct areas in the park, each with its own physical characteristics. Less spectacular than the craggy mountain scenery of Grand Teton, and less imposing than the vast expanses of the Grand Canyon in Arizona, Yellowstone's beauty is subtle, reflecting the changes it has undergone during its explosive past.
Situated on 2.2 million acres, Yellowstone is significantly larger than its sister to the south. Encompassing 3,472 square miles, Yellowstone boasts 310 miles of paved roads and 1,000 miles of backcountry trails, and it is home to more geysers and hot springs than the combined total in the rest of the world. Then comes the (6,000-7,600 ft.), thickening forests dominated by lodgepole pine, broken by meadows where deer, elk, and moose often graze. The transition area between the highest forest and the bare surface above timberline is known as the (7,600-11,300 ft.). Finally, we come to the bare rock at the very top of the continental shelf, where small, hardy plants, such as glacier lilies and sky pilot, bloom briefly after the annual thaw.
When you arrive at the Southern Geyser Basin you might feel that you've been transported through a geologic time warp. Here you will find the largest collections of thermal areas in the world -- there are perhaps 600 geysers and 10,000 geothermal features in the park -- and the largest geysers in Yellowstone. The result: boiling water that is catapulted skyward and barren patches of sterile dirt; hot, bubbling pools that are unimaginably colorful; and, of course, the star of this show, the geyser Old Faithful. Plan on spending at least 80 minutes here, as that's the typical period between the eruptions that send thousands of gallons of boiling water through the sky at a speed exceeding 100 mph. The between Mammoth Hot Springs and the Tower-Roosevelt region, is a high-plains area that is primarily defined by mountains, forests, and broad expanses of river valleys that were created by ice movements. In part two of our Yellowstone National Park landscape we will concentrate on the thermal areas of Yellowstone. This includes the Midway Geyser Basin which is where the Prismatic Springs ( seen above) is located.
Midway Geyser Basin