According to the study, drones were used to observe the lava dome, a viscous plug of lava. The researchers were able to show that the lava dome shows movements on two different time scales: slow expansion and growth of the dome and fast extrusion of viscous lava.
Due to the difficult accessibility and the high risk of collapse or explosion, the imaging of active volcanoes has so far been a great challenge in volcanology.
Scientists equipped a drone with different cameras. They then flew the drone over the crater at various intervals, measuring the movements of the lava flow and a lava dome using a specific type of stereo photography with a precision never seen before.
By comparing the data from the drone, the research team was able to determine the flow velocity, movement patterns and surface temperature of the volcano. These parameters are important for predicting the danger of explosive volcanoes.
The researchers also succeeded in deriving the flow properties of the lava from these data. They showed that the use of drones can help to completely re-measure even the most dangerous and active volcanoes on Earth from a safe distance.
Using a special computer algorithm, the researchers were able to create complete and detailed 3D models from the images. They obtained a 3D topography and temperature model of the volcano with a resolution of only a few centimetres.
Drone missions considerably reduce the risk for volcanologists, as the cameras can be flown directly to the dangerous spots without the scientists having to go near them themselves. Instead, the greatest challenge lies in the post-processing and calculation of the models.