Probing the Multiscale Nature of Crustal Magma Transport

Karlstrom Leif, Berkeley CA

Investigators

Abstract

Dr. Leif Karlstrom has been granted an NSF Earth Sciences postdoctoral fellowship to carry out a research and education plan at Stanford University. He will investigate magma transport processes in the crust on two different scales through modeling of volcanic tremor and statistical inference of arc-scale eruption patterns. The tremor work aims to identify available mechanisms for the origin of seismicity during volcanic eruptions, and will examine long period seismic signatures of different eruption styles with a coupled fluid flow and elastodynamic numerical model. The larger scale aspect of this work will test models of magmatic plumbing with Quaternary eruptions in the Cascades arc. Network inference techniques and Bayesian statistics will be applied to a newly compiled dataset of recent volcanism throughout the Cascades. The goal of this study is to test for the degree to which magma transport is controlled by dynamic internal organization versus external forcing (glaciation, spatially variable tectonic stresses). Magma transport is relevant both for understanding Earth history and volcano-human interactions, but it is largely inaccessible to direct observation. As a result, the mechanics of rising and cooling magmas that generate episodic volcanism are poorly constrained. This work probes the deep structure of volcanoes by modeling patterns of radiated seismic waves during eruptions, and using statistical inference techniques to probe the structure of magma plumbing throughout the Cascades volcanic arc. These studies ask the general question: to what extent can theoretical models represent or predict indirect, remote observations? This question has important implications for the degree to which models and data can be synthesized to interpret the geologic record and assess volcanic hazards. Educational activities associated with this project include leading a field trip to Lassen National Park and co-teaching a course on physical volcanology at Stanford.