Yellowstone National Park occupies nearly 3,500 square miles in Montana, Wyoming, and Idaho. More than 3 million people visit the park every year to see the lush outdoor areas, wildlife, and famous geysers like “Old Faithful.” What people do not come there for are the earthquakes. On Sunday, a 4.8 magnitude earthquake hit Yellowstone National Park. No damage or injuries have yet been reported, and this is the largest earthquake that has occurred in the park since 1980.
Earthquake monitoring is a big deal at Yellowstone. The park sits on top of one of the world’s largest super-volcanoes, the Yellowstone Caldera. In a recent study, the magma chamber where the molten lava gathers in the caldera was determined to be 56 miles long and 19 miles wide. It would be capable of holding 100 sextillion gallons of lava. In other words, the number ten with twenty-two zeros after it. That is an absolutely gigantic amount of lava.
More than 1,000 earthquakes happen every year at Yellowstone. In fact, the area experiences earthquakes every single day, which sometimes number into the 20’s. These daily earthquakes rarely reach over a 3.0 in magnitude, however. In 1959, a 7.5 magnitude earthquake killed 28 people and caused damages exceeding $11 million.
The United States Geological Survey (USGS) has stated that the recent 4.8 magnitude earthquake that hit Yellowstone National Park brought no cause for alarm. Damage seems to have been no greater in extent than some food items falling off of the shelves at a local store.
Scientists have generally been in agreement that a massive eruption at Yellowstone would obliterate most of the United States with lava and ash. Thankfully, the last massive eruption took place over 640,000 years ago, and another at around 1.5 million years before that one.
Judging from the last two massive eruptions, it could be supposed that the super-volcano erupts in million year intervals. However, a third eruption is also known to scientists. Data shows another eruption at the Yellowstone Caldera around 2.1 million years ago. This places the eruptions at 2.1 million and 1.5 million years approximately 640,000 years apart. In other words, because the last eruption known took place around 640,000 years ago, the Yellowstone Caldera could be due to erupt again at any moment.
Smaller eruptions are known to take place at the super-volcano, too. One eruption covered the caldera basin, and probably occurred around 100,000 years ago. The last massive eruption at the Yellowstone Caldera, 640,000 years ago, was more than 1,000 times greater than the eruption at Mount St. Helens in 1980.
Scientists from the USGS monitor the volcano every day from the Yellowstone Volcano Observatory, which was created in 2001. GPS systems at Geyser Basins and elsewhere around Yellowstone give geologists a precise measurement of how much the ground at Yellowstone rises every year. A given year generally sees the ground at Yellowstone rise about 2.75 inches.
The super-volcano at Yellowstone is widely known to be a ticking time bomb. The pristine outdoor vistas, hot springs, and unique wildlife sit atop a disaster of epic proportions waiting to happen. Scientists are doing what they can to understand the phenomenon, but it is quite unique. There are only 5 other super-volcanoes like it around the world. Hopefully, there will be no larger quakes, and the 4.8 magnitude earthquake that just hit Yellowstone National Park will be one of the larger ones on record for many years to come. At any rate, the USGS seems to feel that this is the case at the moment.
By Luke Sargent