Models constraining models: Analogue modelling to assess theoretical uncertainties
Our research group is focused on understanding the movement of magma in the upper crust. Such movement is commonly in the form of a dyke, a sheet of magma that migrates through the crust by continually cracking the crust at the upper end.
A key force allowing dykes to propagate is the buoyancy of the magma, in which relatively-less-dense magma pushes up through the denser crust. More specifically, we are examining how a dike slows down and stops propagating (arrests) and how a dyke accelerates in the vicinity of the surface. This helps us to understand the conditions that can lead to the stalling of a dyke or the occurrence of a volcanic eruption.
Simple “quasi-static” experiments are to be performed, in which a dyke is subjected to a static load and allowed it to evolve into a new static state. Previous experiments have used gravity as the driving force. However, as gravity cannot be turned on and off (thankfully!), we will instead apply a compressive force to one end of the dyke, compressing it and causing it to propagate.
To remove gravity as a factor in propagation, neutrally buoyant liquids will be used to make the dyke. This can be done by introducing a density gradient to the host gelatin and allowing the dyke to propagate laterally at its preferred depth. In order to perform a lateral propagation, a new experimental apparatus will be set up allowing continual examination the conditions for dyke arrest and acceleration while simultaneously benchmarking numerical codes.
In one experiment, a tank is filled with gelatin, which acts similar to the Earth’s crust. Inside the gelatin, a crack filled with oil grows upward towards the surface, which represents magma moving through the crust. A camera in front of the tank tracks what happens inside. An array of cameras positioned above the tank is used to make a 3D model of the surface. As the crack moves up, it begins to affect the surface, which can be measured with these models.
- Earth Observatory of Singapore
- ENSTA ParisTech
Meetings & Abstracts:
Pansino, S, & Taisne, B., Can a dike “feel” a free surface?, Abstract V43B-3109 presented at 2015 Fall Meeting, AGU, San Francisco California 14-18 Dec.
Adel Emadzadeh, Asian School of the Environment, Nanyang Technological University
Allan Derrien, Institut de Physique du Globe de Paris (IPGP)
Kim Pham, ENSTA ParisTech