Noise produces volcanic seismicity, akin to a drumbeat (Vol. 46 No. 4)

A new study shows that relatively small external disturbances play a crucial role in chaotic phenomena like the recent Calbuco volcanic eruption in Chile, leading to drum-beat-like seismicity.

Volcanoes are considered chaotic systems. They are difficult to model because the geophysical and chemical parameters in volcanic eruptions exhibit high levels of uncertainty. Now, the authors have further extended an eruption model—previously developed by other scientists—to the friction force at work between the volcanic plug and volcanic conduit surface. The results provide evidence that volcanic activity can be induced by external noises that would not otherwise have been predicted by the model. The authors show that the external noise is also linked to the appearance of large-amplitude oscillations in the volcanic plug and high seismicity. An increase in noise intensity leads to drumbeat-type plug movement, exhibiting irregular periodicity dependent on noise. Such beat-type behaviour is a building block for understanding the physical mechanisms of volcanic drumbeat seismicity.

D. V. Alexandrov, I. A. Bashkirtseva and L. B. Ryashko, How a small noise generates large-amplitude oscillations in the volcanic plug and produces high seismicity, Eur. Phys. J. B 88, 106 (2015)
[Abstract]