Fluid-triggered seismicity, instability and slip related to volcanic edifice collapse

These twin PhD projects will

(1): Simulate the injection of high temperature fluid to better understand how fluid-driven reactivation may contribute to faulting an instability as applied to volcano flank collapse. Specifically the project will investigate the edifice collapse on the island of Stromboli, a volcano in the north-eastern tip of the Aeolian volcanic arc in the Tyrrehian Sea. Stromboli has suffered numerous mass movement events over the last 13ka that have resulted in depressions and flank collapses such as the “Sciara del Fuoco” and the “Rina Grande – Le Schicciole” slopes (Di Traglia et al., 2018). This is likely the result of strain field reorganisation associated with the development of magma movement and dyke injection, as well as the sector collapses themselves (Tibaldi et al., 2003). The interplay between the regional stress field and the intrusion of north-east striking dykes leads to a complex deformation fabric that is embedded in the fracturing of the local volcanic rocks. Evidence for new dyke sheets, such as lateral creep on the north-western flank of the volcano, suggests that these bodies rise in a horseshoe shape, pushing the Sciara del Fuoco scarp outward toward the sea (Tibaldi et al., 2009) and so provide more space for dykes to occupy.

(2): generate a new geophysical (rock-physics) image as a quantified metric at elevated but modest temperatures. The aim is to take existing laboratory data and to calculate likely source mechanisms for two key types of seismicity. The types of seismicity to be investigated would be; Volcano-Tectonic [VT] (brittle fracture), and Low-Frequency [LF] (primarily driven by rapid fluid flow), as a function of stress and pore fluid decompression/stress, and would be backed up with physical data using X-Ray Computed Tomography [XCT]. In addition, two models will be applied to the data: the crack resonance models of Kumagai and Chouet (2000), and that of Neuberg (Thomas & Neuberg, 2013).