Yellowstone National Park on Dangerous Ground

A Horrific Volcanic Disaster Waiting to Happen

Dec 29, 2008

Old Faithful Geyser, Yellowstone National Park, U.S. Geological Survey

One of the largest super volcanoes in the world lies beneath Yellowstone National Park and nobody knows when it will erupt.

The Yellowstone Plateau volcanic field resulted from three volcanic eruptions that spanned two million years.

The first cycle occurred over two million years ago and it created the Island Park caldera.

The second cycle happened approximately one million years later and it formed the Henry’s Ford caldera situated west of the first caldera.

The third cycle, that occurred 640,000 years ago, shifted to the Yellowstone Plateau and formed the caldera which is present today.

Geysers, steam vents, hot springs and mud pots are all visible signs of geothermic activity. Most of the geothermal areas are located in valleys created by old lava flows and glacial moraines. Other geothermal areas are located where fault lines reach the earth’s surface and at the bottom of slopes where groundwater is more prevalent.

Geothermal Features at Yellowstone Park

Geysers

These are eruptions of scalding hot water. Steam bubbles force water out of the ground and then it subsides when pressure is lost. Old Faithful is the best known geyser.

Fumaroles

Also known as steam vents, these contain very little water and expel steam and gases. Roaring Mountain is an example of a fumarole.

Hot Springs

A convection current is created by heated water cooling as it reaches the surface and then sinks. Then it is replaced by hot water rising from below. Grand Prismatic Spring is an example of a hot spring.

Travertine Terraces

These are created in limestone when hot water bubbles through the rock. The heated water contains carbonate and carbon dioxide is released when the water reaches the surface. Calcium carbonate is deposited as travertine. Mammoth Hot Springs is known as a travertine terrace.

Mudpots

Some acidic hot springs contain little water. Hydrogen sulphide rises from within the earth and is converted into sulphuric acid. This changes rock into clay. Fountain Paint Pot is an example of a mudpot.

Seismic and Volcanic Activity at Yellowstone Park

The Yellowstone Caldera has been under scrutiny for the past 17 years. Satellites monitor the vertical and horizontal motion. There has been constant bulging and deflating detected in the Yellowstone Caldera due to the build up and release of magma.

The Teton Range was formed by thousands of earthquakes occurring over millions of years. Seismic activity allowed the mountains to rise upwards while valleys dropped downwards. Recent studies have proved that the valleys are rising while the mountains are falling.

Earthquakes are constantly occurring at Yellowstone Park. One of the largest earthquakes to hit the western U.S. interior took place at Yellowstone in 1959. It had a magnitude of 7.5.

According to the Yellowstone Park website, “in 2002 alone, there were more than 2350 earthquakes at Yellowstone, including over 500 triggered by the Nov. 2002, M7.9 Denali earthquake.”

The Norris Geyser Basin had an earthquake of 6.1 in 1975. In 2002, there was an increase in geothermal activity in this area and parts had to be closed to visitors.

The University of Utah Seismograph Stations reported, “a light earthquake of magnitude 4.1 occurred at 05:59 AM on March 25, 2008 (MDT). Two earthquakes of magnitude 3.0 or greater occurred within 25 km of the epicenter of this event since 1962. The largest of these events was a magnitude 3.5 on July 20, 1992, 4 miles NE of Fishing Bridge, WY.”

Scientists at the Yellowstone Volcano Observatory (YVO) constantly monitor volcanic and tectonic activity, in addition to discovering more about the behavior of magma beneath the earth’s surface.