• Using infrasound to characterize volcanic emissions at Tolbachik, Karymsky, and Sakurajima volcanoes

      Albert, Sarah; Fee, David; Tape, Carl; Szuberla, Curt (2015-08)
      The work presented herein includes one main body of research on infrasound from Tolbachik Volcano and suggestions for future work on eruption dynamics using infrasound from other volcanoes. We use both regional and local infrasound data to track the dynamics of the 2012-2013 eruption of Tolbachik Volcano, Kamchatka, Russia. Analysis of regional data recorded at the IMS array IS44 in southern Kamchatka, ~384 km from the vent, focuses on the eruption onset in November 2012, while analysis of local data recorded 100-950 m from the vent focuses on activity in February and August 2013. Signals recorded from Tolbachik suggest an increase in eruptive intensity occurred from November 28-29, 2012. Local infrasound data are characterized primarily by repeated, transient explosion signals indicative of gas slug bursts. Three methods are employed to pick slug burst events in February and August, with all methods proving to be effective. The nature of slug bursts makes a monopole acoustic source model particularly fitting, permitting volume outux and slug radius calculations for individual events. Volume outuxes and slug radii distributions provide three possible explanations for the eruption style of Tolbachik Volcano from mid-February to late August. Cumulative outux for slug bursts (i.e. mass of emissions from individual bursts) derived by infrasound for both February and August range from <100 to 3000 kg. These values are greater than infrasound-derived emissions calculated at Pacaya Volcano, but less than those calculated at Mt. Erebus Volcano. From this, we determine slug bursts at Tolbachik Volcano in February and August were larger on average than those at Pacaya Volcano in 2010, but smaller on average than those at Mt. Erebus in 2008. Suggestions for future work are also given after analysis of acoustic waveforms from local infrasound data collected at Karymsky and Sakurajima Volcanoes. Activity at both of these volcanoes ranges from short-duration ash-rich explosions to longer-duration ash-rich explosions. A multiparameter dataset collected at Karymsky Volcano in August 2011 includes infrasound data, gas and ash data, and thermal imagery from eruptive events. Content of gas vs. ash, general plume characteristics, plume altitude above the vent, plume temperature, and SO₂ emission rates are correlated with acoustic waveform families identifed at each volcano using a cross correlation method. This preliminary analysis shows promise for correlating acoustic waveforms with eruptive activity and can likely be improved with future work.