Title: Towards developing a new microphysical model for rock rheology : Integrating acoustic data and thermodynamic constraints
Abstract: Generalized constitutive models are crucial for understanding various solid Earth problems ranging from volcano-magmatic systems, tectonics, subduction zones, and landslides. Despite the development of various theoretical models with damage, laboratory validation remains a significant challenge due to the difficulty in representing the damage state evolution. In this talk, I will present a new framework to address this challenge by incorporating energy conservation laws from Thermodynamics of Irreversible Processes (TIP) into a TIP-informed-Neural Network architecture along with seismic/acoustic waveform features (TIP-INN). The talk will focus on two primary set of results : (a) ) Unsupervised feature selection in acoustic waveforms –Can features in the micro EQs as well as active source coda waveform determine the stress-strain quantitatively? Using acoustic data for Carrara marble spanning the brittle-ductile transition and dimensionality reduction methods, such as UMAP (Uniform Manifold Projection), we show that the acoustics have distinct diagnostic features related to the stress-strain-damage state of the system; (B) Theoretical framework for TIP-INN – I will describe the theoretical framework underlying the constitutive modeling and also present results for a new general TIP-based forward rheology solver that we have developed for thermo-visco-elastic material models (with multiple damage internal parameters). Finally, I will present some present preliminary results towards development of the full TIP-INN model framework including out new Neural network architecture to implement TIP-INN.
Biography: I am currently an Assistant Professor in the Geoscience Department at Penn State and a Packard Fellow (starting 2024). I completed my Ph.D. at UC Berkeley in Spring 2020 and was a Crosby Postdoc Fellow at MIT from 2020-2022. My research focuses on four major themes across Earth and Planetary Science: (A) Volcano Science (Modeling magmatic processes and Submarine volcanism), (B) Planetary geophysics (Planet formation and geodynamics, Planetary science), and (C) Volcano/tectonic-climate interactions (Understanding the impact of solid Earth process on the ocean-atmosphere system across a range of timescales – months to Myr), and (D) Geofluids & Geomechanics (Understanding rock rheology and fluid-rock reactions on a micro-scale and developing thermodynamically consistent upscaled models; using seismic information in the lab & field to investigate processes in real-time for detailed process understanding). In addition, I have a few active projects focused on utilizing my Earth science knowledge for various applications related to energy transition – geothermal energy (especially enhanced geothermal systems at high temperatures), critical mineral discovery (Li, REE, Copper), geologic carbon sequestration (enhanced rock weathering, basalt carbon sequestration),
To join virtually: Zoom
Contact: tmittal@psu.edu
Website: https://sites.google.com/view/tushar-mittal/
Recording: Zoom Recording (will be available within a week after the seminar)