Volatile Content Implications of Increasing Explosivity of the Strombolian Eruptive Style along the Fracture Opening on the NE Villarrica Flank: Minor Eruptive Centers in the Los Nevados Group 2

Potential flank eruptions at the presently active Villarrica, Southern Andes Volcanic Zone (33.3–46 °S) require drawing of a comprehensive scenario eruptive style dynamics, which partially depends on degassing process. The case we consider in this study is from Los Nevados Subgroup 2 (LNG2) and constitutes post-glacial minor centers (MECs) basaltic–andesitic basaltic composition, associated with northeastern Villarrica flank. Petrological studies melt inclusions volatile content olivine determined pre-eruptive conditions shallow magma feeding system (<249 Mpa saturation pressure, 927–1201 °C). model “pressure-dependent” species, measured by Fourier Transform Infrared Microspectrometry (FTIR) (H2O 0.4–3.0 wt.% CO2 114–1586 ppm) electron microprobe (EMP), revealed that fast cooling pyroclasts like vesicular scoria preserve ~1.5 times larger amount CO2, S, Cl, species contained primitive (Fo76–86). Evidence geological mapping drone surveys demonstrated eruption chronology spatial changes all local vents along N45° corridor. mechanism LNG2 degassed plays critical role increasing explosivity uphill volcanic NE sector (<9 km minimum depth) to SW (<8.1 km), where many crystalline ballistic bombs were expulsed, rather than spatter scoria.