Abstract AGU FALL 2001

Jonathan M. Lees

April McGreger

Maurizio Ripepe

Visual Evidence of Seismo-Acoustic Wave Propagation at Mount Etna

Mount Etna commenced eruptive activity in the spring of 2001 with several vents exploding and lava flows extruding from the southeast crater.  In May 2001 we recorded several days of broad band seismic data in conjunction with infrasonic acoustic wave monitors.  During this deployment we noted that infrasonic acoustic waves were observable visually in gasses and clouds above volcanic vents where activity was the strongest.  Digital video recordings show sudden changes in light near the active vents.  The visual observations represent pressure waves passing through the mouth of the vent, subsequently deforming cloud observed as pressure pulses exciting remote fumeroles where normally continuous flow is disturbed by atmospheric pressure waves.  Infrasonic activity on Etna was substantial, occurring every few seconds, although all three active vents each contributed to the background acoustic noise.  Acoustic noise couples into the ground, interfering with the broad band seismic signals used to establish source mechanics and explosion physics.  We present cross-correlation cluster analysis used to discriminate between explosions at numerous vents during the eruptive phases of multi-crater systems such as Etna and Stromboli and compare these to mono-vent explosive activity at Karymsky Volcano, Russia.