P-Wave Attenuation Structure and Melting Processes of the Tonga-Lau Mantle Wedge
Description:
The fast-converging Tonga subduction zone and its adjacent Lau back-arc form a complex system where the melting mechanisms show significant along-strike variations. To estimate melt fraction and further investigate the thermal and rheological structures in the Tonga Lau mantle wedge, we present an improved P-wave attenuation tomography model. We first incorporate independently constrained source parameters to invert for the path-average attenuation operator t*. Then, based on the refined t* dataset, we apply a Bayesian Markov chain Monte Carlo technique to image the Tonga-Lau subduction system's 3D P-wave attenuation structure. Compared to previous models, this new Qp model is built upon a more accurate 3D velocity tomography model and utilizes more precise parameterizations in a spherical coordinate system. The new results exhibit high attenuation anomalies in the Tonga-Lau back-arc mantle and beneath the Taveuni Volcano. With the help of the Very Broadband Rheology (VBR) Calculator (Havlin et al., 2021), we can quantitively estimate along-strike variations in melt fraction and temperature. Preliminary results show an increasing trend of melt fraction from south to north. The highest melt fraction reaches up to ~6.5% beneath the Central Lau Spreading Center.
Session: Earth’s Structure from the Crust to the Core - III
Type: Oral
Date: 5/1/2024
Presentation Time: 02:15 PM (local time)
Presenting Author: Yurong
Student Presenter: Yes
Invited Presentation:
Authors
Yurong Zhang Presenting Author Corresponding Author yurong@msu.edu Michigan State University |
Songqiao Wei swei@msu.edu Michigan State University |
Joseph Byrnes Joseph.Byrnes@nau.edu Northern Arizona University |
Dongdong Tian dtian@cug.edu.cn China University of Geosciences |
Fan Wang wangfa16@msu.edu Michigan State University |
Maximiliano Bezada mbezada@umn.edu University of Minnesota |
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P-Wave Attenuation Structure and Melting Processes of the Tonga-Lau Mantle Wedge
Session
Earth’s Structure from the Crust to the Core