Explosions and periodic tremor at Karymsky volcano, Kamchatka, Russia

• Published in: Geophysical Journal International
• Main Authors: Lees, Jonathan M., Gordeev, Evgenii I., Ripepe, Maurizio
• Format: Text
• Language: English
• Published: Oxford University Press 2004
• Subjects: Volcanology; Geothermics; Fluids and Rocks; Kamchatka
• Online Access: http://gji.oxfordjournals.org/cgi/content/short/158/3/1151; https://doi.org/10.1111/j.1365-246X.2004.02239.x

The explosions of Karymsky volcano often produce signals containing a sequence of repeating pulses recorded on acoustic and seismic sensors, known as chugging. The amplitudes of these pulses correlate with the time interval between pulses. For a given measured acoustic pressure, seismic amplitudes take on arbitrary values up to a specific, empirically determined threshold. Conversely, events with a small seismic amplitude yielded acoustic waves with large variations and large-amplitude seismic events corresponded to large acoustic waves. These observations are not consistent with a source modelled by a resonating conduit. Rather, a model consisting of a sequence of discrete pulses explains the data and provides a framework for understanding the dynamics of degassing at the vent. The physical model for chugging involves a time-varying narrowing vent where gasses are released in a series of oscillations which appear to be harmonic but instead are modelled as short-term transients, or discrete pulses, suggestive of choked flow.