The Emergence of Fumaroles at Kelud Volcano in 2020-2022 : An Indication of A New Magma Supply

After the last VEI 4 eruption in February 2014, Kelud Volcano (East Java, Indonesia) started showing signs of unrest in September 2020. In response to this, we conducted geochemical investigation and visual observation around Kelud crater lake area. New observable phenomena e.g. increased fumarolic activities, crater lake watercolor changed, subaqueous bubbling and gas bubbles in the crater lake, and red deposits found on the rim of crater lake. These phenomena started appearing in September 2020, which correlated with the emergence of deep volcanic earthquakes recorded by Kelud seismic network. The temperature of the crater lake water also increased and became more acidic. Stable isotope data of Oxygen-18 (18O) and Deuterium (2H) fumarole condensate indicate the type of meteoric water, while isotope values of crater lake water indicate a mixture of volcanic and meteoric water. We suggest that ascent of magmatic gases from new magma supply at depth emitted through the lake water, which caused these changes. The period of unrest at Kelud volcano between September 2020 and March 2022 attributed to the deep magma recharge. Join Zoom Meeting : https://u-paris.zoom.us/j/83493006080?pwd=SEQ0c0dwMTcxbEZjK21kYkJxbll2Zz09 ID de réunion : 834 9300 6080 Code secret : 311694