Investigating explosive eruption dynamics with field-, laboratory- and computer-based methods
Fig. 1: Doppler radar measuring the mass and vertical speed of an ash plume at Sabancaya volcano, Peru (J. Gilchrist, F. Donnadieu)
Fig. 2: Analog experiment on a saltwater jet with silica powder modeling an explosive eruption ash column (J. Gilchrist)
Fig. 3: Computer simulation of analog experiment (previous image) showing inner jet and spreading cloud (E. Breard)
How do I study explosive eruptions?
First, I review the literature on specific eruptions and, when possible, I go to volcanoes to study their deposits and observe eruptions visually and with Doppler radar (Fig. 1). Just like a police officer detecting the speed of your car or a meteorologist detecting rain in the atmosphere, we can use Doppler radar to measure the speed and mass of volcanic rocks erupting from a volcano to improve forecasts of volcanic hazards.
Second, with the data and insights gathered from the literature and field work, I go to the lab to conduct fluid dynamics experiments with water and particles to investigate how volcanic jets, plumes and ash clouds rise, collapse and spread in the atmosphere (Fig. 2).
Third, I use the controlled datasets from the lab experiments and eruption datasets from the field to ensure computer simulations are capturing complex multiphase physical processes accurately, which govern how eruptions behave, so that we can develop them further to simulate real eruptions (Fig. 3).
It is not always possible to follow this exact workflow and field-, laboratory- and computer-based methods are all powerful methods on their own. However, where one method is limited another method may be well-suited, therefore combining all three in a single study is desirable.
Fig. 4: Field methods such as direct observations and deposits studies combined with analog experiments and computer simulations are powerful research tools for studying volcanic eruptions. When analog experiments and computer simulations are combined, they complement each other and provide new ways to study eruptions in far greater detail while remaining grounded in reality by the constraints set by field studies.
Using this multi-method research approach I aim to:
Provide a better fundamental understanding of the complex multiphase fluid dynamics governing explosive eruption behavior
Address uncertainties in reconstructions of volcano-climate effects for ancient and historic eruptions and, in turn, forecasts of volcano-climate effects for future eruptions
Develop more detailed models for gravitationally unstable eruption columns
Improve ash cloud hazard forecasting for ongoing and future eruptions
Why study explosive eruptions? Click here to find out!