Time-series analysis of fissure-fed multi-vent activity: a snapshot from the July 2014 eruption of Etna volcano (Italy)
On 5 July 2014, an eruptive fissure opened on the eastern flank of Etna volcano (Italy) at ~3.000 m a.s.l. Strombolian activity and lava effusion occurred simultaneously at two neighbouring vents. In the following weeks, eruptive activity led to the build-up of two cones, tens of meters high, here named Crater N and Crater S. To characterize the short-term (days) dynamics of this multi-vent system, we performed a multi-parametric investigation by means of a dense instrumental network. The experimental setup, deployed on July 15-16th at ca. 300 m from the eruption site, comprised two broadband seismometers and three microphones as well as high speed video and thermal cameras. Thermal analyses enabled us to characterize the style of eruptive activity at each vent. In particular, explosive activity at Crater N featured higher thermal amplitudes and a lower explosion frequency than at Crater S. Several episodes of switching between puffing and Strombolian activity were noted at Crater S through both visual observation and thermal data; oppositely, Crater N exhibited a quasi-periodic activity. The quantification of the eruptive style of each vent enabled us to infer the geometry of the eruptive system: a branched conduit, prone to rapid changes of gas flux accommodated at the most inclined conduit (i.e. Crater S). Accordingly, we were able to correctly interpret acoustic data and thereby extend the characterization of this two-vent system.
KeywordsMulti-vent activity Plumbing system geometry Thermal data Acoustic data
The data used in this work were collected during field campaign performed by the authors and they may be available upon request to the corresponding author. This project was supported by the EU-funded FP7 project MEDiterranean SUpersite Volcanoes (MED-SUV), grant agreement 308665. L.S. wish to thank the ERC Consolidator “CHRONOS” project (Grant No. 612776). L.S. and A.C. thank the project AEOLUS funded by the Fondo di Ricerca di Base of Department of Physics and Geology, University of Perugia. U.K. additionally acknowledges the support by the EU-funded Initial Training Network ‘VERTIGO’, grant agreement 607905. DBD acknowledges the support of the ERC Advanced Grant EVOKES (247076). The authors are grateful to the editors G. Lube and J.D.L. White and to an anonymous reviewer for the detailed comments and fruitful suggestions. We wish also to thank L. Scuderi for the precious help provided during fieldworks.
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