The Wrangell Mountains form the volcanic heart of the park. Covering over 2,000 square miles, the Wrangell Volcanic Field is made up of thousands of lava flows and some of the highest peaks in North America, and includes Mount Wrangell, one of the largest (by volume) active volcanoes in the world.
The Wrangell volcanoes were formed over the last 5 million years by massive eruptions which were the result of tectonic collisions along the Pacific and North American crustal plates. Although this activity has slowed for the past few thousand years, there is still heat at depth, as evidenced by Mount Wrangell's steam plumes, and the series of active mud volcanoes east of Glennallen.
Did You Know?
A very seismatically active spot on the planet, Alaska averages 50 earthquakes annually with a magitude greater than 5.