Reading Lava With Light: A Volcanologist Brings Planetary Imaging to the Parks

Volcanologist Erika Rader was a skeptic. Looking for a postdoctoral project after her PhD, she tried visual near-infrared (VNIR) spectroscopy, a technique planetary scientists use a great deal. She didn't understand it, so she doubted it worked — but she gave it a try, and soon saw many new uses for it in volcanology.

How it works

VNIR imaging shines a band of wavelengths — near-infrared, here — on an object and records which wavelengths are reflected, absorbed or re-emitted. The pattern of reflected light reveals the object's properties.

Rader pointed it at basalt, a volcanic rock she knew well from earlier geochemistry work. VNIR clearly separates basalt's glassy regions from regions with larger crystals.

Why planetary scientists care

• Glassy volcanic rock can signal past water. Lava that flows into water cools differently from lava that flows over land — so glassy regions on other planets can point to water there in the past.
• It's cheap to do from afar. Shining certain wavelengths of light at a planet costs less time and money than sending a spacecraft.

Rader's long-term project, IceCrystal, studies how crystalline lava flows are — including on bodies other than Earth. By imaging lava in national parks, she can help interpret data about lava flows beyond Earth.

So far she has analyzed rocks for it in three parks:

• Bering Land Bridge National Preserve;
• Craters of the Moon National Monument and Preserve;
• Lava Beds National Monument.

Why the parks

National parks are symbols of what we love about Earth, but they can also be some of the best stand-ins for other worlds. Rader works in them because that is where the lava is: they are among the few places where lava flows are preserved, protected and accessible. That preservation also keeps places like Craters of the Moon special — her students were so excited on arrival that they nearly raced one another up the Inferno Cone Overlook, until snow cooled their enthusiasm a little.

Safer science, safer people

• No more drilling. Before, scientists had to drill into lava to test its density, viscosity or composition. Now they can get the same data from the surface, and they're working toward fully remote sensing.
• Keeping away from active lava. Imaging lets researchers study flows without getting close.
• Better forecasts. Imaging active lava gives more accurate readings of its composition, a key to its viscosity — how readily it flows. Knowing that improves models of lava flows, which help keep people and parks safe.

Sources

Based on Emma Stefanacci, "A New Look at Lava," National Park Service, Bering Land Bridge National Preserve, Craters of the Moon National Monument and Preserve, and Lava Beds National Monument; a work of the United States government in the public domain. Erika Rader's words are summarized; rewritten in hubnx's own words.