The Cascade Volcanic Arc


The Cascade Volcanic Arc

The Cascade volcanic arc is a series of volcanoes that sit within the Cascade Range formed through the subduction of Earth's tectonic plates. This created a string of volcanoes spanning from North California up through Oregon and Washington and into Canada. This article outlines all that you need to know about this fiery land from its formations and features to its eruptions.

Introduction to The Cascade Volcanic Arc

The Cascade Volcanic Arc is a chain of volcanoes sitting along the Cascadia subduction zone running for over 700 miles from northern California through to British Columbia in Canada. It covers a distance of over 700 miles, featuring 20 major volcanoes and nearly 4,000 volcanic vents. Formed over 30 million years ago, the Cascade Arc features the second-highest volume of volcanic activity in the U.S – the first being Yellowstone National Park. Indeed, every volcanic eruption within the last two centuries in the contiguous U.S. has come from the Cascade Volcanic Arc.

The volcanoes of the Cascade Range are part of what's commonly known as the Pacific Ring of Fire. A region that circumferences the edge of the Pacific Ocean, so-called as it hosts 75% of the world's volcanic activity. The four largest volcanic eruptions of the current geological epoch occurred in the Pacific Ring of Fire, one of which being Mount Mazama, part of the Cascade Volcanic Arc in Oregon, approximately 7,700 years ago.

The most recent activity of the Cascade Volcanic Arc, occurred at Lassen Peak, California, between 1914 and 1917, and the major eruption of Mount St. Helens, Washington, in 1980. Due to the significance of the volcanic activity, and increasing population growth in the Pacific Northwest, several volcanoes, such as Mount Rainier, the highest peak in the Cascade Range, are under special observation and study. On average, a volcano will erupt in the Cascade Range once or twice per century with at least 7 volcanoes having erupted since the Declaration of Independence in 1776.