Characteristics of the beginning of the 2019 eruptive crisis at Ubinas volcano (Peru)

Ubinas volcano has produced moderate explosive eruptions during the last ~500 years. With 26 eruptive periods, this composite cone is the most active volcano in Peru. The 2006–2009 and 2013–2017 eruptions impacted people, agriculture, and livestock within 15 km of the vent. On 24 June 2019 a new eruptive cycle started with minor emissions of tephra and aerosols. Activity increased on July 19 with an explosion beginning at 2:30 AM (local time). At that time, seismicity also increased with a predominance of LP-type signals. Two clearly differentiated and wind-controlled volcanic plumes were observed. Initially, the plume reached 6500 m above the summit and the main dispersion axis was ESE, dispersing ash as far as 300 km away to the villages of Jesus de Machaca and Catacora, Bolivia, where ash fall disrupted people’s daily activities. While the first plume was still active, a 1200-m-high secondary plume developed and was dispersed to the SE, reaching more than 200 km away into the Tacna region (Peru). After...