Variability in eruption style and associated very long period events at Fuego volcano, Guatemala

Repeated short‐term deployments of seismic, infrasound, video, and gas‐emission instruments at Fuego volcano, Guatemala have revealed three types of very long period (VLP) events associated with conduit sealing, pressure accumulation, and release. In 2008, ash‐rich explosions issued from a vent on the western flank and produced one type of VLP (Type 1). Impulsive, bomb‐rich explosions from the summit vent in 2009 produced a shorter period VLP (Type 2), but also generated ash release. Type 3 VLP events occurred during ash‐free exhalations from the summit in 2008 and had waveform shapes similar to Type 2 events. Weak infrasound records for Type 1 explosions compared to Type 2 suggest lower pressures and higher magma porosity for Type 1. Type 3 events correlate with spikes in SO2 emission rate and are driven by partial sealing and rapid release of ash‐free gas at the summit vent. Variations in the VLP period may provide a new tool for monitoring conditions within the conduit. Key PointsVariations in very‐long‐period earthquakes are related to eruption styleA class of very‐long‐period earthquakes is clearly related to gas emissionVLPs may inform about conditions within the conduit