Towards Imaging Yellowstone’s Crustal Magmatic System with Ambient Noise Adjoint Tomography

Session: Full-Waveform Inversion: Recent Advances and Applications [Poster]
Type: Poster
Date: 4/29/2020
Time: 08:00 AM
Room: Ballroom
Description: 

The Yellowstone hotspot hosts a complex crustal magmatic system that drives hydrothermal activity, seismicity and periodic ground deformation. Seismic tomography has constrained the presence of a partially molten magma reservoir at middle-to-upper crustal depths centered below the caldera, but key aspects of the system such as the total volume and distribution of melt remain open questions. Interpretations of previous tomographic images of Yellowstone are complicated by an incomplete understanding of how transcrustal magmatic systems affect seismic waveforms. In particular, studies based on traditional body wave or surface wave travel time tomography may underestimate the seismic velocity anomaly of the magma reservoir because first arriving energy may be diffracted around strong low velocity anomalies. To overcome the limitations of previous tomographic imaging, further efforts should take advantage of recent theoretical and computational advances in adjoint tomography that incorporate more accurate wave propagation physics.

Here, we report on our progress towards imaging Yellowstone’s crustal magmatic system using ambient noise adjoint tomography. We present a dataset of empirical Green’s functions derived from ambient noise cross correlations between more than 250 broadband seismic stations belonging to several networks deployed in the Yellowstone region over the past two decades. In order to assess the applicability of adjoint tomography to our dataset, we perform numerical wave propagation experiments aimed at investigating how geophysically plausible models of Yellowstone’s magma reservoir affect the seismic wavefield. End member scenarios of the size and melt fraction of the magma reservoir are informed by previous seismic tomography and scattered wave imaging studies. Our results illustrate the importance of 3D wave propagation effects on seismic waveforms and guide our future efforts at developing a new adjoint tomography model of Yellowstone’s magmatic system.

Presenting Author: Ross Maguire

Authors