Towards a 3D Reflectivity Model of Erebus Volcano, Antarctica, from Body Wave Seismic Interferometry applied to Strombolian Eruption Coda
CHAPUT, J. A., New Mexico Institute of Mining and Technology, Socorro, NM, firstname.lastname@example.org; ASTER, R. C., New Mexico Institute of Mining and Technology, Socorro, NM, email@example.com; ANTHONY, R., New Mexico Institute of Mining and Technology, Socorro, NM, ; KNOX, H., New Mexico Institute of Mining and Technology, Socorro, NM, ; KYLE, P. R., New Mexico Institute of Mining and Technology, Socorro, NM,
Passive imaging in volcanic media has garnered much attention over the past few years with the development of cross-correlation methodologies utilizing multiply scattered wavefields. For persistently active volcanoes, or for a set of repeating artificial seismic sources, it is also possible to utilize seismic coda as a short-period noise source to recover high-resolution information about the volcanic edifice and its temporal evolution. Building on the success of this methodology, as previously applied to the Mount Erebus permanent broadband network, we demonstrate that the Strombolian eruption coda recorded on the volcano satisfies modal equipartioning after only a few seconds, which is a key theoretical component of Seismic Interferometry (SI). Furthermore, we present a novel approach for interpreting structural details by retrieving body wave Green’s function estimates for arbitrarily rotated data in 3D space. In doing so, we maximize the signal to noise ratio of an arrival on a given component of the Green’s function to constrain the wave type and ray path of that arrival. We present early results using array-processed coda-derived Green’s functions for a 2007-2008 dense near-summit deployment on Mt Erebus, incorporating over 140 3-component broadband and short period stations. We aim to recover 3D reflectivity details of Erebus volcano and its shallow magmatic system, and to investigate temporally evolving structural details where we have adequate event coverage in time. Other phenomena on Mt Erebus, such as VLP-SP Strombolian eruption lag variations (Knox et al., 2011) and long-term temporal variations of reflector properties observed in previous single-station interferometry efforts (Chaput et al, 2011) are also presented and corroborated with these new observations.