A New Look at Lava

By Emma Stefanacci

Dr. Erika Rader imaging preserved lava at Bering Land Bridge National Preserve.

Courtesy of Erika Rader

PhD in hand, Erika Rader, Doctor Erika Rader - “licensed” volcanologist, looked for a postdoctoral research project. Unsure what might be best for the long-term, she experimented with visual near-infrared (VNIR) spectroscopy equipment. She heard that this imaging could show cool things about rocks but still had her doubts. Her first thought about VNIR was “‘I don’t understand this and therefore I don’t believe it works, but planetary scientists sure use it a lot so maybe I should give it a think.” Soon after, she realized that this technology had many new applications to volcanology that she wanted to share with others.

Imaging like this shines a specific range of wavelengths, near-infrared in the case of VNIR, on an object and catalogs the wavelengths that are reflected, absorbed, or reemitted. The type of light reflected tells us about different properties of the object.

The objects Dr. Rader chose were basalt, a type of volcanic rock and one with which she was familiar because of her previous geochemistry research. VNIR clearly distinguishes the glassy regions of basalt from regions with larger crystals.

Glassy regions of volcanic materials interest planetary scientists because they can indicate the presence of past water on other planets. Yes, you read that correctly, water on other planets. When lava flows into water, it cools differently than when it flows over land. Also, VNIR imaging is widely used by planetary scientists since it takes less time and money to shoot certain wavelengths of light at a planet than to send a spacecraft.

The VNIR experience expanded Dr. Rader’s horizons, from the Earth systems that most geochemists focus on, to the vast implications of geochemistry in space. Dr. Rader is working on a long-term research project, called IceCrystal, looking at the crystallinity of lava flows, including on planetary bodies not named Earth. “I’ve analyzed rocks for this project in Bering Land Bridge National Preserve, Craters of the Moon National Monument and Preserve, and Lava Beds National Monument so far.” Using VNIR imaging on different lava here, Dr. Rader can help to interpret the data about lava flows that aren’t here on Earth.

Tim Orr and Jessica Larsen from the Alaska Volcano Observatory walking on preserved lava at Bering Land Bridge National Preserve.

Courtesy of Erika Rader

You may not think it because national parks are often symbols of (Earthen) nature and what we love about our home planet, but they can also be some of the best analogues for other places in our galaxy. National parks are different from other research sites, especially for a geochemist, because they are more consciously preserved and protected.

Dr. Rader said that she was working specifically in national parks because that is where the lava is. They are some of the few places where lava is preserved, protected, and accessible. The preservation also means that parks like Craters of the Moon maintain their uniqueness which captures the interest of everyone. Dr. Rader said that the descriptions of Craters of the Moon are so cool that “Energy was high when we drove into the park, and they [her students] practically raced each other up the Inferno Cone Overlook.” The view incited many “wow”s until the oncoming snow slightly dampened the excitement.

Not only does VNIR allow for some out of this world research prospects, but it can make the entire field of volcanology, the study of volcanoes, safer. Using imaging techniques to understand lava flows means that researchers don’t have to be physically near the lava. Before this method, scientists would have to drill into the (preserved) lava in order to test the density, viscosity, or composition. Now they can get the same data from the surface and are working towards fully remote sensing.

The researchers are safer, and they can help make all of us safer too. Imaging active lava can give more accurate readings about the composition which is an important factor in understanding the viscosity of the lava—how readily it flows. Knowing the viscosity leads to better models about lava flows which are what can keep our people and our parks safe.