A Seismo-Acoustic Investigation of a Localized Crater Terrace Collapse
at Stromboli Volcano
Abstract
Interpreting seismo-acoustic signals is critical for assessing and
characterizing changes in volcanic vents and has implications for
interpreting volcanic unrest. This is especially relevant for Stromboli
volcano (Italy), an active stratovolcano with a complex plumbing system,
continuous activity, and recurring paroxysms. Stromboli is known for its
consistent Strombolian style of eruption, multiple active vents on its
crater terrace, and for occasional structural modifications including
explosive excavation and/or collapsing craters due to near-surface
changes to the plumbing system. This study addresses a single localized
collapse of the crater terrace, occurring in May of 2019, when one of
Stromboli’s vents changed from a pronounced hornito to a pit crater,
resulting in a shift in eruption style at this vent from jetting to
Strombolian. The days before and after this transition were recorded
with eight infrasound sensors and three seismic geophones located on the
crater terrace. We investigate the seismo-acoustic timing of these
signals as well as the ratio between seismic and acoustic energy to
identify changes associated with eruptive signals and associated
variations in location of the eruptive sources. This work highlights the
effectiveness of seismo-acoustic data analysis, provides insight into
Stromboli’s structural modifications, and builds a foundation for
focused analysis of seismo-acoustic signals associated with Stromboli
and other open-vent volcanic systems.