The big destination in the US for volcano-lovers is Hawai’i Volcanoes National Park; however, you have plenty of options for seeing more mature volcanic landscapes in the continental US.
The Cascade Range
The Cascade Range is a chain of volcanoes that originated in the interaction between tectonic plates. As the oceanic Juan de Fuca plate slides below the North American plate, the heat and pressure release water in its rocks, creating steam that eventually turns the Earth’s mantle into magma, some of which sooner or later finds its way to the surface.
The youngest volcanic landscape in this part of the world is the region around Mount St. Helens, which erupted catastrophically in 1980. You can learn more about this volcano at Mount St. Helens National Volcanic Monument, which includes Johnston Ridge Observatory. Johnston Ridge is in the center of the 1980 blast zone; the observatory is open from mid-May through October and offers interpretive displays and ranger talks. (The facility also gathers geological data and transmits it to the USGS Cascades Volcano Observatory.) Ape Cave, the third-longest lava tube in North America, is open year-round, and guided walks are available during the summer. In Silverlake, Washington, Mount St. Helens Visitor Center at Silver Lake (open year-round) offers information about the volcano (including a step-in model) and the ecosystems that were affected by its eruption. You can also take short or long hikes of various levels of difficulty on and around Mount St. Helens.
Lava Beds National Monument, in northeastern California, is located on the northeastern side of Medicine Lake Volcano, which is the largest volcano by volume in the Cascades. In addition to cinder cones (the remnants of explosive eruptions of magma under pressure) and lava flows, the monument also contains lava tube caves, some of which are open to visitors. You can also explore local history and culture, including Native American rock art, and enjoy the high-altitude desert landscape of the monument.
A bit south of Lava Beds, at the northern end of California’s central valley, is Lassen Volcanic National Park; Lassen Peak is the southernmost volcano in the Cascades, and the park contains four other volcanoes. In addition to landscapes dominated by lava flows and cinder cones, this park also features active geothermal features such as hot springs, mud pots, and sulfur vents.
The second largest volcano in the Cascades by volume is Newberry Volcano, which is near Bend, Oregon. In the Newberry National Volcanic Monument, you can visit the caldera of the volcano, hike through the Big Obsidian Flow, a relatively recent lava flow (1300 years ago) consisting of shiny obsidian as well as some pumice, explore a lava tube cave, and climb or drive to the top of Lava Butte, a cinder cone volcano. You can also hike the Lava Cast Forest, a slightly older lava flow (6000 years old) that formed casts of the trees along its path.
I’ll also mention Crater Lake National Park in Oregon and Mount Rainier National Park in Washington. The central feature of each park is a volcanic peak, but these parks also contain numerous other features, and someday I’ll write about them in another post.
The Great Rift of Idaho
Craters of the Moon National Monument and Preserve, in central Idaho, is located on the Snake River Plain. The lava fields here are the result of magma rising to the surface along the Great Rift of Idaho, a line of fractures in the crust. The lava flows that have been dated so far are 2,000 to 15,000 years old. (Much further back in time, the hot spot currently under Yellowstone was under this area.) The monument showcases a wealth of volcanic features; the lava fields provide a natural textbook on the various forms that molten basalt can take as it solidifies.
This monument is located near the center line for the August 21 total solar eclipse; there will be astronomy-related activities at Craters of the Moon and an eclipse viewing opportunity in the nearby town of Arco.
Volcanic fields in Arizona and New Mexico
Arizona contains a volcanic mountain range, the San Francisco Peaks north of Flagstaff. The volcanoes here are attributed to a geological hot spot that the crust slid over. The oldest volcanoes, on the west side of the volcanic field, are about 6 million years old. Those on the east side are younger; Sunset Crater, at around 1,000 years, is the youngest. At Sunset Crater Volcano National Monument, you can visit the volcanic features on foot or check out the exhibits and programs at the visitor center.
Capulin Volcano is a fairly symmetrical cinder cone in northeastern New Mexico; it’s part of the extinct Raton-Clayton volcanic field and is also thought to have formed when the North American plate passed over a hot spot. At Capulin Volcano National Monument, you can find exhibits and interpretive programs at a visitor center at the base of the volcano. A paved road will take you to the rim of the volcano, which stands out dramatically above the surrounding plains and thus offers great views of the region. Several hiking trails are available near the base and at the top of the mountain.
The stark and dramatic lava fields of El Malpais National Monument, in west-central New Mexico near Grants, gave this region the Spanish name malpais, or badlands. El Malpais is part of the Zuni-Bandera volcanic field. The volcanic activity here is attributed to the presence of the Rio Grande Rift (which is very slowly pulling New Mexico apart) and a series of faults called the Jemez Lineament; these weak spots in the crust make it easier for magma to break through. You can learn about the monument at the visitor center, which is just south of I-40. Explore the monument itself by visiting various sites along New Mexico state roads 117 and 53 or following one of the hiking trails. There are also lava tube caves that you can visit (with a permit from the visitor center).
The monument offers a few other things of note. Botany fans, you can find cinder phacelia (Phacelia serrata) in the US only here and at Sunset Crater National Monument. This flowering plant grows only on volcanic cinders. In addition, the oldest Douglas firs in the southwestern US grow on the lava flows on the west side El Malpais National Monument.