Towards detecting, classifying, locating and leveraging distributed events in strongly scattering media

This study consists of one branch of an ongoing push to understand, locate, and leverage distributed local events on volcanoes with the dual goal of segmenting volcanic and non-volcanic activity and directly imaging the shallow volcanic edifice. Typically, locating small events on volcanoes is particularly difficult due to their emergent appearance and lack of discernable ballistic waves, precluding any metrics related to travel time. Furthermore, edifice imaging through passive approaches is generally limited due to a lack of stable frequency information above ~1 Hz, truncating surface wave sensitivity to mid-crustal scales. Here, we show a two-pronged approach to tackling these problems: 1) The scattering structure of the volcano is studied in detail using active sources and lava lake eruptions coupled with Monte Carlo Radiative Transfer simulations, permitting a full understanding of seismogram envelopes for a given source location. 2) Coda correlations of distributed icequakes and eruptions have been shown to yield very high-quality Green’s functions at frequencies up to 10 Hz. Beyond cutting scatter-based imaging, these can be used to greatly extend the frequency range of dispersion curves, and thus yield valuable upper edifice information that can be coupled with matrix-based scattering imaging effort.