An Out-of-This-World Landscape: Interview with a Craters of the Moon Geologist

In the high desert of southern Idaho lies a vast, stark landscape of black basalt, deep craters, and jagged lava flows. Craters of the Moon National Monument & Preserve looks less like the American West and more like the surface of another world. To understand how this bizarre topography formed and why it attracted the attention of NASA, we spoke with Dr. Elena Vance, a research geologist who has spent decades studying Idaho's volcanic history.

Science Weekly: Dr. Vance, thank you for joining us. To start, how did Craters of the Moon get its name, and is it actually related to the moon?

Dr. Elena Vance: Thank you for having me! The area received its name because early explorers and geologists felt the vast fields of dark, barren lava resembled the lunar surface. While it wasn't created by meteor impacts like the actual moon's craters, the volcanic features here are structurally very similar to the basaltic plains found on the moon, which are called maria. It is a wonderfully accurate nickname for a place that feels entirely alien.

Science Weekly: Most people associate volcanoes with towering peaks like Mount Rainier or Mount St. Helens. How did the volcanic activity here differ from those famous volcanoes?

Dr. Elena Vance: That is a common misconception. The volcanic activity at Craters of the Moon did not come from a single, explosive mountain peak. Instead, it was created by a series of deep cracks in the Earth's crust known as the Great Rift. Over the last 15,000 years, molten basaltic magma welled up through these fissures during eight major eruptive periods. The lava didn't explode violently; rather, it oozed and flowed like thick syrup, spreading across the landscape and cooling into various textures. This type of gentle, oozing eruption is called a fissure eruption, and it created the massive lava fields we see today.

Science Weekly: What are the different types of lava formations visitors can see there?

Dr. Elena Vance: The monument is a living textbook of basaltic volcanism. You will find two primary types of lava flows here, which we refer to by their Hawaiian names: pahoehoe and a'a. Pahoehoe lava is smooth, billowy, or ropey. It forms when highly fluid lava cools slowly, allowing a thin skin to wrinkle as the molten rock continues to flow beneath it. In contrast, a'a lava is incredibly jagged, sharp, and rough. It forms when cooler, thicker lava moves rapidly, breaking the cooling surface into chaotic, blocky chunks. Additionally, visitors can explore cinder cones, which are steep hills formed by volcanic froth and splutter accumulating around a vent, and massive lava tubes, which are underground caves formed when the outer crust of a lava flow hardened while the molten interior drained away.

Science Weekly: In the late 1960s, NASA took a keen interest in this Idaho landscape. Why did Apollo astronauts train at Craters of the Moon?

Dr. Elena Vance: In 1969, NASA was preparing to send humans to the moon. The astronauts were highly trained pilots, but they were not geologists. NASA needed them to become scientific observers who could select the most valuable rock samples to bring back to Earth. Craters of the Moon was selected as a prime training ground because its volcanic geology is an excellent terrestrial analog—a place on Earth that mimics the environmental conditions and geological features of another celestial body. By walking the rugged basalt fields of Idaho, astronauts like Alan Shepard and Edgar Mitchell learned how to identify volcanic features, navigate harsh terrain, and practice the field geology techniques they would later use on the lunar surface.

Science Weekly: Is NASA still involved with Craters of the Moon today?

Dr. Elena Vance: Absolutely. The partnership never really ended. Today, planetary scientists use the preserve to prepare for missions to Mars. Because Mars is also covered in basaltic rock, researchers use Craters of the Moon to test robotic rovers, practice drone-based mapping, and study extremophiles—microscopic organisms that thrive in the harsh, nutrient-poor environments of lava tubes. By studying how life survives in these volcanic caves, scientists gain clues about where to look for signs of past or present life on Mars. It is incredible to think that this quiet corner of Idaho continues to play a vital role in the future of space exploration.