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)
#UPGOERFIVE Challenge - My research explained with the 10,000 most common words in the English Language
Hot stuff!
In a safe space at school, I study how hot and heavy groups of air, water, and rocks (stuff) come out of the ground really fast, play with each other, and eats cold air to try and fly into lighter air way above the ground. If the hot stuff doesn't have many rocks, moves fast, and eats a lot of cold air, it will go up and stay up where it can change the air around the world and break flying buses of people. If the hot stuff has a lot of rocks, moves slow, and does not eat a lot of cold air, it will go up and come down where it can run people over on the ground. What do you need to know? Stay away from hot stuff coming out of the ground really fast!
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.
Research goals
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!