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Probabilistic Teleseismic Tomography of the Alaskan Mantle With Corrections for Distant Structure

Description: 

Seismic tomography provides a window into the mantle expressions of the tectonic processes that assembled Alaska. Tomographic models have been used to constrain the accretion of the Yakutat Terrane, the origin of the Denali Gap and Wrangell Volcanic Field, and the long-term history of the subduction. In order to estimate the uncertainty in models of the Alaskan mantle and the geometry of structures within it, we apply regional-scale transdimensional Bayesian tomography. This approach has several advantages, including accurate amplitudes and measures of uncertainty for velocity variations. Targeting the mid-mantle beneath Alaska requires the use of teleseismic data, but seismic structure outside the area of study introduces traveltime variance that is not constrained by a regional-scale model. This results in pessimistic error bars for velocity and reduces the confidence of conclusions drawn from the model. It is therefore necessary to find a means of compensating for uncertainty introduced by distant structure.

We present a method for estimating these effects and apply it to the reduction of error bars on a new model of the Alaskan mantle. We demonstrate the effectiveness of the method with data calculated in existing global models before applying it to USArray, global, and local array data. With the corrected traveltimes, a new model of the Alaskan mantle with improved uncertainty estimates will be produced, enabling the testing of hypotheses about mantle structure.

Session: Structure and Behavior of the Alaska-Aleutian Subduction Zone [Poster Session]

Type: Poster

Date: 5/3/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Nathaniel

Student Presenter: Yes

Invited Presentation: 

Authors