This study presents optical geodetic observations to constrain the sources responsible for long-period volcanic earthquakes, which are coincident with frequent explosive eruptions at Santiaguito Volcano, Guatemala. It is found that acceleration in deformation of the volcanic dome, extracted from the high-resolution optical image processing, is coincident with recorded long-period seismic sources. On the basis of these observations, abrupt mass shift of solidified domes, conduit magma or magma pads seem to be part of the mechanism responsible for generating long-period earthquakes at silicic volcanic systems.
- Jeffrey B. Johnson
- Jonathan M. Lees
- Nick Varley