Coupled High Speed Imaging and Seismo-Acoustic Recordings of Strombolian Explosions at Etna, July 2014: Implications for Source Processes and Signal Inversions.

Friday, 18 December 2015: 15:10
307 (Moscone South)
Jacopo Taddeucci1, Elisabetta Del Bello1, Piergiorgio Scarlato1, Tullio Ricci2, Daniele Andronico1, Ulrich Kueppers3, Andrea Cannata4, Joern Sesterhenn5 and Laura Spina6, (1)National Institute of Geophysics and Volcanology, Rome, Italy, (2)INGV National Institute of Geophysics and Volcanology, Rome, Italy, (3)Ludwig Maximilians University of Munich, Munich, Germany, (4)INGV National Institute of Geophysics and Volcanology, Catania, Italy, (5)Technische Universitat Berlin, Berlin, Germany, (6)LMU, Munich, Germany
Seismic and acoustic surveillance is routinely performed at several persistent activity volcanoes worldwide. However, interpretation of the signals associated with explosive activity is still equivocal, due to both source variability and the intrinsically limited information carried by the waves. Comparison and cross-correlation of the geophysical quantities with other information in general and visual recording in particular is therefore actively sought. At Etna (Italy) in July 2014, short-lived Strombolian explosions ejected bomb- to lapilli-sized, molten pyroclasts at a remarkably repeatable time interval of about two seconds, offering a rare occasion to systematically investigate the seismic and acoustic fields radiated by this common volcanic source. We deployed FAMoUS (FAst, MUltiparametric Setup for the study of explosive activity) at 260 meters from the vents, recording more than 60 explosions in thermal and visible high-speed videos (50 to 500 frames per second) and broadband seismic and acoustic instruments (1 to 10000 Hz for the acoustic and from 0.01 to 30 Hz for the seismic). Analysis of this dataset highlights nonlinear relationships between the exit velocity and mass of ejecta and the amplitude and frequency of the acoustic signals. It also allows comparing different methods to estimate source depth, and to validate existing theory on the coupling of airwaves with ground motion.