Because it's not officially a 'dead' volcano - it's just dormant. Additionally, the caldera covers such a vast area that, in the event of a 'super eruption', the amount of material ejected would affect the Earth for centuries to come. Possibly resulting in the extinction of all life on this planet !
The Yellowstone volcano is usually called a supervolcano.
supervolcano
The Yellowstone volcano is usually called a supervolcano.
The Yellowstone Caldera, also known as the Yellowstone Supervolcano, is a volcanic caldera and supervolcano estimated to be an area of about 34 X 45 miles (55 X 72 km).
The caldera that covers most of Yellowstone Park was produced by a supervolcano. A supervolcano is an explosive volcano capable of producing an eruption with an ejecta volume greater than 1,000 cubic kilometers. The Yellowstone Caldera is one of the largest and most active supervolcanoes in the world.
The Kileua volcano in Hawaii was recently listed in this spot, though many people think this is an odd choice. Here's a link to the Top Ten Dangerous Volcanoes, too.
One of only a dozen "super volcanos" in the world. When super volcanos explode it changes life on earth. The last time one went off was Mt. Toba 70,000 years ago.In more technical terms, the Yellowstone volcano is a caldera. Most Caldera volcanoes start out as stratovolcanoes, but this one appears to be an exception.
That is not true about Lake Toba. They recently discovered Lava in the Super Volcano and it is considered restless. Yellowstone could not hold a candle to what Lake Toba can do the world.
No. Most of Yellowstone lies outside of the Yellowstone Caldera, though this caldera still takes up a large portion of the park. A larger portion of the park is in the older Island Park Caldera, which partly overlaps the Yellowstone Caldera. This still takes up a minority of the park.
At Yellowstone, we see the caldera or what we call a supervolcano. The volcanic profile of Yellowstone in its past is one of a massive eruption that dwarfs anything we understand in current knowledge. Use the link below to the Wikipedia post on the supervolcano to learn more.
No. Most of Yellowstone is outside of the caldera.
Most scientists believe that Yellowstone is not truly active and that they would be able to detect if the Yellowstone volcano was going to erupt years before it erupted. But there is no way to no for sure if the Yellowstone caldera is truly active (building up for an eruption).