Time-Resolved Seismic Tomography Detects Magma Intrusions at Mount Etna

Abstract

The continuous volcanic and seismic activity at Mount Etna makes this volcano an important laboratory for seismological and geophysical studies. We used repeated three-dimensional tomography to detect variations in elastic parameters during different volcanic cycles, before and during the October 2002-January 2003 flank eruption. Well-defined anomalous low P- to S-wave velocity ratio volumes were revealed. Absent during the pre-eruptive period, the anomalies trace the intrusion of volatile-rich (>/=4 weight percent) basaltic magma, most of which rose up only a few months before the onset of eruption. The observed time changes of velocity anomalies suggest that four-dimensional tomography provides a basis for more efficient volcano monitoring and short- and midterm eruption forecasting of explosive activity.

Multiscale Seismic Tomography Imaging of Volcanic Complexes

“…Most seismic events occur at depths between 23 and 28 km. This enables favorable illumination of the crustal structures by seismic rays and creates better conditions for tomographic inversion compared to most other volcanoes, for example, Etna (Patanè et al, 2006). It is interesting that the depth distribution of seismicity over time seems to correlate with major eruptions of the Kluchevskoy volcano.…”

Fluid ascent during the 2004–2005 unrest at Mt. Spurr inferred from seismic tomography

“…Moreover, recent time-lapse tomography studies of Mt. Etna [Patanè et al, 2006] and Kluchevskoy volcano [Koulakov et al, 2012] have demonstrated that seismic structures may evolve in time to reflect the reallocation of volatiles, partial melt and stress. It is possible that the structure corresponding to the 1992 eruption period reported in Power et al [1998] may be different than that observed in 2005.…”

Towards forecasting volcanic eruptions using seismic noise

“…More recently, repeated seismic tomographies (12) has been used to detect seismic velocity variations within Mount Etna over periods of a few years. This method reveals variations of the internal volcanic structure before and after an eruption.…”