Characterization and interpretation of volcanic activity at Karymsky Volcano, Kamchatka, Russia, using observations of infrasound, volcanic emissions, and thermal imagery

Abstract

A multiparameter data set including measurements of infrasound, volcanic emissions, and thermal imagery is used to characterize and interpret diverse volcanic activity observed during field campaigns in August 2011 and July 2012 at Karymsky Volcano, Kamchatka, Russia. Four activity types are visually identified and characterized according to: SO2 emission rate, ash mass, event duration, peak temperature, thermal radiation energy, infrasound onset and frequency, reduced infrasonic pressure, and acoustic energy. These activity types include: (1) ash explosions, (2) pulsatory degassing, (3) gas jetting, and (4) explosive eruption. Unique infrasound signals are associated with all four activity types suggesting that infrasound can be used to help remotely and continuously detect and characterize volcanic activity at Karymsky and other similar volcanoes. Our observations suggest that SO2 is emitted continuously, though in varying abundance, while ash is emitted discontinuously and is only associated with certain types of activity. Our data set supports previous models that attribute variations in surface activity to changes in conduit permeability at Karymsky Volcano. Evidence for a decrease in conduit permeability as a trigger for ash explosions and explosive eruption activity types is supported by weakened but still detectable SO2 emission rates prior to eruption, along with the highly impulsive infrasonic onset and large reduced infrasound pressure indicating high pressure at the vent. We speculate that changes in conduit permeability at Karymsky Volcano result from changes in magma supply from the shallow‐crustal storage region though additional measurements are required to validate this hypothesis.