HypoSVI: Hypocenter inversion with Stein variational inference and Physics Informed Neural Networks

TL;DR

This paper presents HypoSVI, a probabilistic hypocenter inversion method using Stein variational inference combined with physics-informed neural networks to efficiently handle complex posterior distributions in seismic localization.

Contribution

The paper introduces a novel approach integrating Stein variational inference with physics-informed neural networks for hypocenter inversion, enabling rapid, scalable, and multimodal posterior estimation.

Findings

Handles highly multimodal posterior distributions effectively

Scales efficiently with the number of differential times

Eliminates the need for travel time tables for different seismic network geometries

Abstract

We introduce a scheme for probabilistic hypocenter inversion with Stein variational inference. Our approach uses a differentiable forward model in the form of a physics informed neural network, which we train to solve the Eikonal equation. This allows for rapid approximation of the posterior by iteratively optimizing a collection of particles against a kernelized Stein discrepancy. We show that the method is well-equipped to handle highly multimodal posterior distributions, which are common in hypocentral inverse problems. A suite of experiments is performed to examine the influence of the various hyperparameters. Once trained, the method is valid for any seismic network geometry within the study area without the need to build travel time tables. We show that the computational demands scale efficiently with the number of differential times, making it ideal for large-N sensing technologies like Distributed Acoustic Sensing. The techniques outlined in this manuscript have considerable implications beyond just ray-tracing procedures, with the work flow applicable to other fields with computationally expensive inversion procedures such as full waveform inversion.