Collecting field data in volcanic landscapes using small UAS (sUAS)/drones

The last several years have seen a very rapid increase in the development and availability of unmanned aerial vehicles/systems (UAV or UAS), more commonly called "drones." UAS are remotely-operated aerial vehicles that can be fixed-wing planes, helicopters, or aerial systems with multiple propellers. Small versions of UAS, here called "sUAS," in particular, have become so prevalent that they can be easily purchased at general retail stores. This paper seeks to review and summarize the use of sUAS in volcanic research. Given their size, low cost, and relative durability, sUAS provide a light-weight tool platform that is easy to transport to field locations; quick to set-up; and easy to launch, and control. They require very little launch and recovery space. Because of these characteristics, sUAS are useful in collecting immediate and realtime aerial data, especially in remote, inaccessible, dynamic, and/or hazardous, volcanic environments. In volcanic areas, sUAS have been used for mapping, sample collection, thermal imaging, magnetic surveys, slope stability studies, and as platforms for sensors to measure outgassing of CO2 and SO2. They are also becoming invaluable for real-time hazard assessment during and after an eruption. They are, however, limited by their flight time, which is greatly affected by wind speeds. Since they are predominately made of plastic, they are also impacted by the high thermal temperatures found in active volcanic areas, which can degrade their structure and performance. With continued technological improvement however, sUAS have the potential to dramatically improve our ability to collect field data. Because of additional natural, technological, and legal challenges related to their use, it is critical that users be aware of, and adhere to, all national and local laws associated with sUAS. (C) 2019 Elsevier B.V.