Editor's note: Yellowstone Caldera Chronicles is a weekly column written by scientists and collaborators of the Yellowstone Volcano Observatory. This week's contribution is from Mark Stelten, research geologist with the U.S. Geological Survey and deputy Scientist-in-Charge of the Yellowstone Volcano Observatory.

The United States hosts two of the world’s most famous volcanic systems: Yellowstone and Hawaiʻi. These systems a well known for producing large volumes of magma through time and leaving chains of volcanic features in their wake, although they do so in very different ways.

Yellowstone and the Hawaiian Islands are some of the most spectacular examples of active volcanic systems in the world, each drawing millions of visitors annually. These volcanic systems are separated by over 3,000 mi (almost 5,000 km) and have dramatically different behaviors and appearances. Yellowstone doesn’t produce tall volcanic features but instead forms large depressions in the ground, referred to as calderas, due to explosive eruptions of rhyolite magma. After formation, Yellowstone’s calderas tend to fill with viscous rhyolite lava flows and domes that from broad plateaus or steep dome-like structures that are often covered with lodgepole pine trees.

In contrast, volcanic activity in Hawaiʻi tends to build broad shield volcanoes like Mauna Loa (the largest active volcano on Earth) that are composed of numerous fluid lava flows and stand above the surrounding landscape. Hawaiian volcanoes are often capped by calderas, albeit much smaller than those produced by Yellowstone and that formed by collapse due to emission of lava flows, rather an explosive eruptions. Hawaiian volcanoes erupt much more frequently than Yellowstone, typically producing fluid basalt lavas, but individual eruptions tend to be much smaller than those from Yellowstone.

Despite these differences in eruptive behavior and outward appearance, Yellowstone and Hawaiʻi have some deeply rooted similarities. Most volcanic systems around the world are related to either subduction zones, where one crustal tectonic plate slides under another (as beneath the Cascade Range in the western US), or at divergent plate margins, where magma ascends as the crust is being pulled apart (often in the middle of ocean basins like along the mid-Atlantic Ridge). Volcanism in Hawaiʻi and Yellowstone, however, is instead driven by mantle plumes, which are regions where the Earth’s mantle is anomalously hot and buoyantly upwelling. As the hot mantle rises to shallower depths it causes melting, which in turn leads to the development of a magmatic system that can produce volcanic eruptions.

Mantle plumes operate independently of plate tectonics and remain mostly stationary as the Earth’s tectonic plates move above them. As a result, magmatic systems like those in Hawaiʻi and Yellowstone produce chains of volcanoes that have an age progression along their lengths. For example, over the past 16 million years, the hotspot currently feeding Yellowstone caldera produced several caldera systems extending from McDermitt Caldera in southeastern Oregon and northern Nevada to Yellowstone caldera in northwest Wyoming. Each of these now-buried volcanic systems was similar to Yellowstone caldera in that they produced large explosive eruptions before plate motion carried the system far enough away from the hotpot that access to the mantle plume was cut off. Eventually, a new volcanic center formed to the northeast of the previous one above the new crustal location of the mantle plume. The eastern Snake River Plain of southern Idaho marks this chain of “ancient Yellowstones” that gets older as you move to the southeast from Yellowstone caldera.

Map of the Northwestern United States showing major volcanic features associated with the mantle plume currently underneath Yellowstone caldera. Colors indicate general basaltic (blues) versus rhyolitic (reds) compositions, with shades indicating age (darker shades are older). Rough outlines of calderas that formed due to the Yellowstone hotspot are given, with numbers indicating approximate ages in millions of years.

Similarly, the hotspot currently under Hawaiʻi is responsible for producing the Hawaiian Ridge-Emperor Seamount chain over the past 80 million years. Volcanoes in that chain get older the farther northwest you go across the Pacific Ocean from the Hawaiian Islands. The oldest “ancient Hawaiʻis” are located off the coast of Kamchatka, Russia.

Map of the Pacific Ocean basin showing volcanoes associated with the Hawaiian hotspot. Vectors indicate Pacific Plate motion relative to presumed fixed mantle hot spot in millimeters per year. Gray lines indicate fracture zones. Numbers along the Emperor Seamounts chain show the age of volcanism in millions of years. Ocean floor ages indicated by colored shades and derived from imagery available on EarthByte.

Given that Yellowstone and Hawaiʻi are both powered by mantle plumes, why do these volcanic systems behave so differently? There are many reasons, but perhaps the most significant is the nature of the crust in the two locations. Hawaiʻi is located on oceanic crust, which is much thinner (~10 km, or ~6 mi) than the continental crust present at Yellowstone (which is ~45 km, or ~28 mi, thick). Due to the thinner crust underneath Hawaiʻi, magma is able to rise more quickly and easily. This means the magma doesn’t have time to crystallize or interact with the crust and instead tends to erupt as runny, or low viscosity, basaltic lava flows. Eruptions also tend to be more frequent and smaller in volume. In contrast, the thick continental crust underneath Yellowstone prevents magma from easily ascending. As a result, this magma stalls and accumulates in the crust. Over time this process has led to the development of a large magmatic system that spans most of the crust underneath Yellowstone and includes a large rhyolite magma reservoir in the upper crust (at depths of 5 to 19 km, or about 3 to 12 mi) that feeds Yellowstone’s dramatic eruptions.

Despite their outward differences, the fundamental engines that power volcanism in Yellowstone and Hawaiʻi are quite similar. So the next time you need a Hawaiian vacation, consider visiting the Yellowstone region. There’s a lot of Aloha in southern Idaho and northwestern Wyoming.