VolKilau: Volcano Rapid Response Balloon Campaign During the 2018 Kilauea Eruption

After nearly 35 years of stable activity, the Kilauea volcanic system in Hawaiʽi, went through sudden changes in May 2018 with the emergence of 20 volcanic fissures along the Lower Eastern Rift Zone(LERZ) destroying 700 homes in Leilani Estates and forcing more than 2000 people to evacuate. Volcanic emissions lasted for several months between June and September 2018 leading to low visibility and poor air quality in Hawaiʽi and across the Western Pacific. The NASA-funded VolKilau mission was rapidly mounted and conducted between 11-18 June 2018 to: i) Profile volcanic emissions with SO2and aerosol measurements, ii) Validate satellite observations and iii) Be prepared for the next large volcanic eruption. Through a series of balloon-borne measurements with tethered and free released launches, we measured SO2 concentration, aerosol concentration and optical properties 60 to 80km downwind from the volcanic fissures using gas sensors, optical particle counters, backscatter sondes, and an aerosol impactor. While most of measurements made during the Kilauea eruption were ground-based, the VolKilau mission represented a unique opportunity to characterize plume properties, constrain emission profiles, study early chemistry involving the conversion of SO2 into sulfuric acid and understand the influence of water clouds in the removal of SO2. Our team continues to be better prepared for deploying in the event of a major volcanic eruption