Spatially-Heterogeneous Causal Bayesian Networks for Seismic Multi-Hazard Estimation: A Variational Approach with Gaussian Processes and Normalizing Flows
Xuechun Li, Shan Gao, Runyu Gao, Susu Xu
TL;DR
Spatial-VCBN addresses the challenge of post-earthquake multi-hazard estimation by modeling spatially varying causal relationships using a Gaussian Process prior over latent spatial effects, combined with invertible normalizing flows to capture non-Gaussian distributions of causal parameters. The coefficients controlling hazards-to-damage relationships, $v^{l}$, are generated as $v^{l} = f_{K_{v}} \circ \cdots \circ f_1(z_{v}^{l})$ with $oldsymbol{z}_{v} \sim \mathcal{GP}(m_v(\mathbf{GF}), k_v(\mathbf{GF},\mathbf{GF}'))$, enabling location-dependent, non-linear causal behavior. Inference uses a sparse GP with inducing points and a stochastic variational framework, achieving near $0.94$ seconds per $km^2$ on GPU, and delivering up to $35.2\%$ AUC improvements over priors and $5.5\%$ over state-of-the-art baselines across Haiti, Puerto Rico, and Turkey-Syria earthquakes. The method decouples co-located hazards, improves robustness to noisy remote-sensing signals, and offers practically actionable, spatially-resolved hazard assessments for rapid disaster response and risk reduction.
Abstract
Post-earthquake hazard and impact estimation are critical for effective disaster response, yet current approaches face significant limitations. Traditional models employ fixed parameters regardless of geographical context, misrepresenting how seismic effects vary across diverse landscapes, while remote sensing technologies struggle to distinguish between co-located hazards. We address these challenges with a spatially-aware causal Bayesian network that decouples co-located hazards by modeling their causal relationships with location-specific parameters. Our framework integrates sensing observations, latent variables, and spatial heterogeneity through a novel combination of Gaussian Processes with normalizing flows, enabling us to capture how same earthquake produces different effects across varied geological and topographical features. Evaluations across three earthquakes demonstrate Spatial-VCBN achieves Area Under the Curve (AUC) improvements of up to 35.2% over existing methods. These results highlight the critical importance of modeling spatial heterogeneity in causal mechanisms for accurate disaster assessment, with direct implications for improving emergency response resource allocation.
