Mud volcanism and creepy mud flows: A new model

Mud volcanism is a widespread geological phenomenon characterized by spectacular mud flow deposits extending for kilometers. However, only a few eruptive events have been reported to be long-lasting and voluminous enough to create such extensive flows. We report findings from a multidisciplinary investigation conducted after three eruptions occurring since August 2022 at the Lokbatan mud volcano in Azerbaijan. During these three short-lived events, only a moderate volume of mud breccia was expelled around the crater site. However, field observations show that these events promoted the downslope motion of the >1-km-long older mud flow. Electrical tomography reveals a conductive unit at ∼25 m depth below the volcano, which lubricates the detachment upon which sediments slide. Cross-checking legacy satellite imagery (from 2009) combined with InSAR data (from 2014) reveals that this type of movement was already occurring as early as 2009, indicating a long-lasting process. Our findings suggest that kilometer-sized mud flows observed at other mud volcanoes may not stem from single, voluminous eruptions, as previously thought, but from gradual sliding processes initiated by new loads of erupted material. This mechanism is essential for understanding the dynamics of mud volcanoes on Earth.