Nuclear, Particle, Astroparticle and Cosmology (NUPAC) Seminars
Candidacy Exam: An Interdisciplinary Approach to Better Understanding the Complexity of Volcanoes and Their Processes
Presented by Katherine Cosburn, UNM
It is an undeniable fact that, for as long as there has been human civilization, there has been human interaction with volcanoes. As such, there is appreciable need to better understand the processes that drive volcanic activity in order to better observe, predict, and assess associated hazards and mitigate potential disaster. Like as it is with most of the natural world, however, the problem is complex and beneath every volcano exist elaborate magmatic systems that are made manifest at the surface as a wide spectrum of eruptive behaviour. Due to their sub-surface nature these systems have historically been poorly understood, but modern advancements in technology have allowed us to gain important insight into these inner workings. In this talk I will go over a couple of research projects aimed at addressing these complex problems. The first is a novel imaging technique utilizing muon tomography in a joint inversion with gravity measurements to resolve the sub-surface density structure of the mesa underneath the town of Los Alamos, New Mexico. The well-characterized nature of the density structure in this area allows us to test the strengths and weaknesses of our inversion technique, important to guiding similar and future studies related to imaging sub-surface volcanic structures. The second project is aimed at analysing the topographic form of stratovolcanoes (e.g. Mt Fuji in Japan). Here we develop a model to help explain the striking conical shape and pattern of cylindrical symmetry exhibited by many of these volcanoes and what processes might lead to a deviation from such symmetry. We explain any departure from axisymmetry as a result of both exogenic (surface) and endogenic (sub-surface) processes, paying particular attention to the sub-surface factors, which we model via displacements at the surface due to the intrusion of magma from a statistical distribution of tensile dislocations beneath a volcanic edifice. Finally, we validate our model using the topographic shape of a diverse number of stratovolcanoes from around the world.
2:00 pm, Tuesday, April 21, 2020
https://unm.zoom.us/j/92518994798
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