Dynamics of soap bubble bursting and its implications to volcano acoustics

TL;DR

This study investigates how the bursting dynamics of gas bubbles in magma influence the acoustic signals emitted, revealing that rupture time affects signal strength and challenging the use of acoustic measurements to infer internal overpressure.

Contribution

It provides new insights into the physical mechanisms of bubble bursting in volcanic conduits and their acoustic signatures, with implications for volcano monitoring.

Findings

Acoustic signal amplitude depends on bubble rupture time.

Measurement of atmospheric acoustic pressure alone cannot determine internal overpressure.

Low energy transfer observed between infrasound, seismic, and explosive signals.

Abstract

In order to assess the physical mechanisms at stake when giant gas bubbles burst at the top of a magma conduit, laboratory experiments have been performed. An overpressurized gas cavity is initially closed by a thin liquid film, which suddenly bursts. The acoustic signal produced by the bursting is investigated. The key result is that the amplitude and energy of the acoustic signal strongly depend on the film rupture time. As the rupture time is uncontrolled in the experiments and in the field, the measurement of the acoustic excess pressure in the atmosphere, alone, cannot provide any information on the overpressure inside the bubble before explosion. This could explain the low energy partitioning between infrasound, seismic and explosive dynamics often observed on volcanoes.