The motivation of my research is to advance structural and source seismic imaging beyond conventional travel time imaging methods by exploiting the full set of information contained in the elastic (or slightly anelastic) wavefield. I develop and validate new methods in this direction resulting in increased image resolution and reduced imaging uncertainty in upper crustal settings relevant to seismic exploration, seismic hazards, and energy transition research. A key application of this work is to enable new discoveries in Earth science, especially in volcanology, by providing seismic evidence to test and support geological hypotheses, using advanced methods, data, and high-performance computing. I also apply deep learning tools to classify explosions and earthquakes in seismic time series data, which helps to facilitate a fast and automated workflow to characterize increasingly large local catalogs.