Multiparameter quantification of gas release during weak Strombolian eruptions at Pacaya Volcano, Guatemala

[1] Activity at Pacaya volcano, Guatemala is characterized by persistent degassing, coupled at times with lava effusion and/or coincident Strombolian-style explosions. We used 0.25 Hz sample rate sulfur dioxide emission data from a UV camera and coincident infrasound recordings to investigate the link between varied emission rates and infrasound events. Degassing rates varied on two scales during this study; smaller, more rapid variations on the scale of 1 to 3 minutes are superimposed on larger, slower changes over 30 minutes to 1 hour. The acoustic record was dominated by repeated N-shaped events characteristic of Strombolian explosions. Because of the high-resolution of the gas measurements, we were able to calculate gas masses for individual explosions from both datasets and find the two estimates agree within an order of magnitude. The infrasound explosion records correlate with small pulses in degassing, but the longer-term degassing trends may represent a deeper process.