Inflation Leading to a Slow Slip Event and Volcanic Unrest at Mount Etna in 2016: Insights From CGPS Data. Issue 24 (23rd December 2017)

• Record Type: Journal Article
• Authors: Bruno, V.; Mattia, M.; Montgomery‐Brown, E.; Rossi, M.; Scandura, D.
• Is Part Of: Geophysical research letters. Volume 44:Issue 24(2017)
• Page Start: 12, 141
• Page End: 12, 149
• Publication Date: 2017-12-23
• Subjects: Mount Etna volcano -- Slow Slip Event -- CGPS data -- volcanic source modeling; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2017GL075744
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Global Positioning System (CGPS) data from Mount Etna between May 2015 and September 2016 show intense inflation and a concurrent Slow Slip Event (SSE) from 11 December 2015 to 17 May 2016. In May 2016, an eruptive phase started from the summit craters, temporarily stopping the ongoing inflation. The CGPS data presented here give us the opportunity to determine (1) the source of the inflating body, (2) the strain rate parameters highlighting shear strain rate accumulating along NE Rift and S Rift, (3) the magnitude of the SSE, and (4) possible interaction between modeled sources and other flank structures through stress calculations. By analytical inversion, we find an inflating source 5.5 km under the summit (4.4 km below sea level) and flank slip in a fragmented shallow structure accommodating displacements equivalent to a magnitude M w 6.1 earthquake. These large displacements reflect a complex mechanism of rotations indicated by the inversion of CGPS data for strain rate parameters. At the scale of the volcano, these processes can be considered precursors of seismic activity in the eastern flank of the volcano but concentrated mainly on the northern boundary of the mobile eastern flank along the Pernicana Fault and in the area of the Timpe Fault System. Key Points: We detected inflation, likely due to magma, beneath Mount Etna's summit region During the inflation, we detected a new Slow Slip Event on the eastern flank of Mount Etna We construct a model of the inflation leading to the slow slip supported by stress and strain calculations Plain Language Summary: In this manuscript we provide a detailed analysis of a period of inflation at Mount Etna. During this inflation, a slow slip event occurred on Mount Etna's eastern flank. We model both the inflation phase and the slow slip event to investigate the sources and the possible relationships between these sources and the volcanic and seismic activity at Mount Etna.