Deformation-controlled long-period seismicity in low-cohesion volcanic sediments

Volcano seismicity is an important tool in monitoring and forecasting activity at volcanoes globally. Volcanic earthquakes show diverse spectral characteristics, of which shallow long-period (low-frequency) long-duration tremor are generally interpreted as indicators fluid migration, potential eruption precursors. Here we that a common low-cohesion volcanic sediment from the Campi Flegrei caldera (Italy) produces low-frequency it undergoes deformation dry conditions. We employed acoustic-emission rock-deformation experiments range strain rates to produce events that, when normalized for scale, were spectrally indistinguishable observed natural settings. The generation these signals was enhanced lower laboratory rates. Correlated X-ray tomography samples before after constrained source distributed damage. Long-period may be generated by weak material subsurface, not solely movement, according rock experiments.