Source characterization for an explosion during the 2009 eruption of Redoubt Volcano from very-long-period seismic waves

► Very-long-period seismic waves were observed during the 2009 Redoubt eruption. ► Particle motions point to a source region below the crater. ► Using waveform inversion, we find a source at an elevation of 0.8 km ASL. ► The limited number of stations causes there to be a spurious solution. ► Our study is important for interpretation when there are limited stations.