PhD Oral Defense of Pansino Stephen Gregory: An Experimental Approach to Dike Propagation: The Effects of Stress, Solidification and Internal Flow
- Oral Defense
About the Event:
This presentation addresses dike propagation from various vantage points, in order to construct a holistic conceptual model of how they behave in nature. Dikes are important to study, in that they are fundamental to magma migration. Most basaltic eruptions (e.g. the large 2018 eruption at Kilauea, Hawai’i and the 2014 eruption of Bardarbunga, Iceland) are fed by dikes. Recharge events, which supplies fresh magma from depth to shallow magma reservoirs and are associated to eruptions (e.g. the 1991 eruption of Pinatubo, Philippines), are commonly considered to be fed by propagating dikes.
I will discuss dike propagation dynamics in terms of their internal flow, their form of propagation, their response to external stresses and thermal effects that affect the form of magma supply; indeed there are many factors at playing controlling how dikes propagate. The research focuses on analogue modeling, which involves constructing simplified, small scale versions of behaviors that are observed in nature. For example, injecting oil into a block of solid gelatin generates an experimental dike that represents a buoyant magma, ascending through the crust. In order to compare the experimental results with nature, I use various dimensionless numbers, which ensure that there is similarity between the two analogous systems by maintaining proportionality between various forces.
This defense provides a broad view on the factors controlling dike propagation and evolution, from analysis on the driving forces of propagation to the effect of the stresses in the medium to the thermal viability and vulnerability to solidification. Since magmatic dikes propagate in response to such various processes, this approach offers valuable and fundamental insights into their nature.
Oral Examination Committee:
- Associate Professor Pham Quang Cuong, Nanyang Technological University, Singapore (Chairman)
- Associate Professor Adam Switzer, Nanyang Technological University, Singapore (Oral Examiner)
- Associate Professor Fidel Costa, Nanyang Technological University, Singapore (Mentor)
- Assistant Professor Benoit Taisne, Nanyang Technological University, Singapore
- Dr Lorenzo Masia, University of Twente
About the Speaker:
Stephen Pansino received his B.A. in Mechanical Engineering in 2010 from the University of Pittsburgh (USA) and an MSc in Geology from SUNY at Buffalo (USA). His Master’s work involved performing analogue experiments examining two-phase bubbly and slug flow in a volcanic conduit, with application to volcanoes with lava lakes. Stephen joined NTU as an IGS student in 2014, working with Dr. Benoit Taisne. He received a grant from the Dr. Stephen Riady Geosciences Scholar Fund to attend a field course in Alaska and perform experiments on dike propagation near a pressurized magmatic reservoir. During his Ph.D., he used analogue experiments to study various behaviors associated to dike propagation.