This is a past event
Please join us for a seminar given by Dr Luca De Siena on “Energy-dependent tomography of volcanic cones and calderas: towards exploiting full-waveform information.”
Abstract:
In volcanic media, strong lateral variations in the properties a ffecting seismic wave propagation produce physical phenomena, which generally corrupt results based on ray-propagation and linear optics, and cannot be modelled by full-waveform deterministic techniques. We may not callthose eff ects "noise", as they still provide us with information on the Earth heterogeneity: the problem is that these eff ects are stochastic in nature. A reliable 2D and/or 3D synthetic model of the energies produced by seismic sources and travelling through a volcanic medium can be obtained including drastic changes of the scattering properties of the volcanic area (as a caldera rim, a volcanic cone, or a melt/fluid reservoir) as boundary conditions of radiative transfer theory equations. With this in mind, we study and image attenuation and scattering of seismic wavesin di erent volcanic media, in search of magmatic chambers, fluid batches, gas reservoirs, and sediment-fi lled faults. We span attenuation and scattering tomography of continental volcanoes (Mt. Vesuvius and Campi Flegrei, southern Italy) and volcanic islands (Deception, Antartica, and Tenerife, Spain), to show recent advancements of these two techniques. Finally, we obtain results using data recorded during the 2004 eruption of the Mount St. Helens volcano (Washington State, USA), where we were able to discriminate feeding systems from complex tectonic interactions,and started building a forward model for reliable 4D imaging. This is a "full-envelope" tomography, which could lead to the application of full-waveform tomography to volcanic areas by better listening to what the volcano is "telling us".
- Speaker
- Dr Luca De Siena
- Venue
- St Mary's Building, Room 105