Three‐dimensional P‐wave velocity structure of Mt. Etna, Italy

Abstract

Abstract. The three-dimensional P-wave velocity structure of Mt. Etna is determined to depths of 15 km by tomographic inversion of first arrival times from local earthquakes recorded by a network of 29 permanent and temporary seismographs. Results show a near-vertical low-velocity zone that extends from beneath the central craters to a depth of 10 km. This lowvelocity region is coincident with a band of steeply-dipping seismicity, suggesting a magmatic conduit that feeds the summit eruptions. The most prominent structure is an approximately 8-km-diameter high-velocity body located between 2 and 12 km depth below the southeast flank of the volcano. This high-velocity body is interpreted as a remnant mafic intrusion that is an important structural feature influencing both volcanism and east flank slope stability and faulting.

Relating seismic velocities, thermal cracking and permeability in Mt. Etna and Iceland basalts

“…These results clearly demonstrate that lava-flow basalt from Etna contains a much higher level of crack damage than the columnar basalt from Iceland that is formed in an intrusive environment. Our results can explain the low seismic velocities (approximately 3-4 km/s) inferred for basaltic volcanic edifices, which are essentially formed from piles of lava flows, and the higher values (approximately 5-6 km/s) observed for intrusive cooled magma bodies, such as dykes emplaced in the volcanic edifice [9,10,20,21].…”

Seismic tomography of Central São Miguel, Azores

“…For these reasons, it has been applied to investigate the interior of several volcanoes such as Redoubt [Benz et al, 1996], Etna [Villaseñor et al, 1998], Kilauea [Dawson et al, 1999] and Vesuvio [Scarpa et al, 2002], and calderas, for example Campi Flegrei [Zollo et al, 2003].…”

The Bay of Naples (southern Italy): Constraints on the volcanic structures inferred from a dense seismic survey

“…This has been widely used in other volcanic areas [e.g., Benz et al, 1996;Villaseñor et al, 1998;Dawson et al, 1999;Scarpa et al, 2002], and it is based on a linearized iterative approach: in a given velocity distribution a 3-D time grid of the first arrival is built for each station, solving the Eikonal equation. This task is achieved using a finite differences approach [Vidale, 1990;Podvin and Lecomte, 1991].…”