Studying volcanic eruptions with aerial drones.

In 1984, the volcano Mauna Loa erupted in Hawaii, sending ribbons of lava winding down its slopes. Geologist and former pilot David Pieri of the California Institute of Technology’s Jet Propulsion Laboratory wanted to get measurements and observation of every part of the lava flow to predict its ultimate route and length. However, he only had one way to see the lava: with a helicopter. “I remember being so frustrated because you could only see what was right in front of you,” says Pieri. “It was a 22-kilometer lava flow and by the time we flew to the bottom, we had no idea what was going on at the top. There was no way to collect data at multiple locations.” Moreover, the helicopter was pummeled by turbulence from the 800 °C lava, making data collection difficult and even a little dangerous. In March of this year, Pieri helped direct a half-dozen Dragon Eye unmanned aerial vehicles (UAVs)—the same drones that the military uses for some reconnaissance missions—into the volcanic plume of the Turrialba volcano in Costa Rica. By flying multiple UAVs at once, Pieri and his colleagues could track the chemical characteristics of many spots in the gas and ash clouds simultaneously. More importantly, the risk to human life was lessened. When jet airplanes fly into a volcanic plume, their blades become clogged with melted ash. Researchers who study volcanoes, as well as aviation safety experts, worried about where airplanes can safely fly, have mostly relied on infrared data collected by satellites to determine the thickness and density of an ash plume. Less energy getting through means a bigger, denser cloud. However, these measurements are largely unvalidated, says Pieri, and not quantitative enough. Pieri wants to use UAVs, which have electric engines that take in little air (or ash), to get more accurate data from right inside the ash cloud. The small Dragon Eye UAVs, which weigh 5.9 pounds and have a wingspan of 3.75 feet, can only carry a payload of 500 grams, but Pieri’s team has managed to fit two cameras, a sulfur dioxide sensor, a particulate sensor, a nanoparticle counter, and a vacuum bottle that sucks up ash and gas samples into the UAVs. So far, the researchers have conducted trial runs to make sure the UAVs and associated sensors work. However, they’re planning experiments to study how the chemistry of plumes change over time, and with increased distance from a volcano. These data may help develop models to predict volcanic activity and damage, and aid in decision-making regarding where aircraft can safely fly. “There’s a whole new arena of detailed observations and new kinds of data that we could never get before, that now we can get in a relatively inexpensive way,” says Pieri. Pieri has access to almost 90 UAVs managed by the National Aeronautics and Space Administration Ames Research Center, all retired by the US Marine Corps, to use to continue tweaking his protocols, improving his sensors, and pushing the limits of science. Pieri not only imagines flying more UAVs into ash clouds, but designing UAVs that can land directly on a lava flow. “This technology has limitless possibilities,” he says. Drones like the one shown being launched are making the detailed investigation of volcanic eruptions and lava flows possible. Image courtesy of David Pieri.