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When you travel across the United States, you can see many sights made by volcanoes. You know what cone-shaped volcanoes look like. But you can keep an eye out for many other volcanic landscapes too.
Some volcanoes build mountains, but only during the active part of their lives. When a volcano stops erupting, it starts to wear down, or erode. Eventually, only parts of the original mountain are left.
Other volcanoes don’t build mountains at all. Instead, their lava floods the land, drowning hills and valleys. Sometimes during an eruption, the top of a volcanic cone falls in, and a crater forms. A crater is also called a caldera. Craters can be from hundreds of feet wide to tens of miles across!
Let’s visit some of America’s volcanic landmarks.
▲ Grand Canyon, AZ: About a million years ago, lava poured over the west walls of the Grand Canyon. It plugged up the Colorado River. The river eventually cut through the rock and formed Lava Falls. Rafting through the rapids at Lava Falls can be a thrilling ride.
◀ Ship Rock, NM: Ship Rock is a lava plug that formed in the throat of a volcano. Erosion wore away the volcanic cone around it. Now Ship Rock looms above the desert like a skyscraper.
Petrified Forest, AZ: These trees are actually fossil logs. They may have been pulled up during a volcanic explosion more than 200 million years ago. Then they were buried by mudflows, like when Mount St. Helens erupted in 1980. Minerals in the volcanic ash turned the trees to rock. ▶
▲ Crater Lake, OR: Some craters fill with water and become lakes. At 2,000 feet deep, Crater Lake is the deepest lake in the United States. It’s so deep, you could stack two Eiffel Towers in it!
◀ Sunset Crater, AZ: This classic cinder cone is only 900 years old. Minerals such as sulfur and iron create the sunsetlike colors.
Craters of the Moon National Monument, ID: You may not get to the Moon, but you can explore this alien landscape instead. These lava fields and cinder cones are in Idaho. Apollo astronauts trained here before they went to the Moon. ▶
◀ Mount St. Helens, WA: A “forest of stone” formed here about 1,900 years ago. Lava covered the slopes and burned into giant fir trees. The hollow casts of the trees make special places for exploring.
▲ Hudson Palisades, NJ: About 200 million years ago, North America and Africa were part of one landmass. Then they began rifting apart, or separating. Giant cracks formed near where New York City is now. Magma was pushed out, and you can see it today. It’s in the high basalt cliffs along the west side of the Hudson River.
Old Faithful
▲ Yellowstone National Park, WY: Steam and hot water gush from Old Faithful about once an hour. Yellowstone National Park is on top of a hotspot. It has more active geysers than all the rest of the world put together! Yellowstone hasn’t seen an eruption for 70,000 years. But the geysers show us the area is still volcanically active.
◀ A geyser is like a teakettle under the ground. Rainwater seeps into the Earth, and hot magma heats the water until it turns into steam. The hot steam rises and jets into the sky as a geyser.
