Basin-scale geometric focusing: a probabilistic-geometric framework for global tsunami exposure assessment and the 2025 Kamchatka Peninsula tsunami

Abdolali, Ali, Lam, Michael-Angelo Y.-H., Kadri, Usama ORCID: https://orcid.org/0000-0002-5441-1812, Malej, Matt, Filimonov, Maxim ORCID: https://orcid.org/0000-0002-3144-9252 and Shi, Fengyan 2026. Basin-scale geometric focusing: a probabilistic-geometric framework for global tsunami exposure assessment and the 2025 Kamchatka Peninsula tsunami. Natural Hazards and Earth System Sciences 26 (8) , pp. 3597-3616. 10.5194/nhess-26-3597-2026

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Abstract

We present a hybrid probabilistic-geometric framework that integrates probabilistic earthquake statistics with large-scale ray-tracing simulations to efficiently map global coastal tsunami exposure. Utilizing a catalog of historical tsunamigenic events and the Gutenberg–Richter relation, we derive probabilistic weights for 9000 rays released across potential fault zones. The simulated ray pathways reveal persisting bathymetry-driven energy convergence patterns that govern far-field coastal focusing and shadowing. The geometric framework's predictive power is demonstrated using the 2025 M 8.8 Kamchatka Peninsula earthquake and the 2011 M 9.0 Tohoku-oki event. Validation against these events utilizes phase-corrected FUNWAVE-TVD simulations and in-situ DART observations. The resulting ray-based coastal focusing patterns display strong qualitative and quantitative spatial agreement (e.g., Spearman's ρ = 0.66 and ρ = 0.63, respectively) with the transoceanic maximum wave amplitudes from the high-fidelity FUNWAVE-TVD model. This agreement confirms the hybrid probabilistic-geometric approach as a scalable and computationally efficient tool for rapidly identifying transoceanic focusing potential and prioritizing coastal regions for high-resolution exposure assessment, mapping relative geometric convergence.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Schools > Computer Science & Informatics Schools > Mathematics
Publisher:	Copernicus Publications
ISSN:	1561-8633
Date of First Compliant Deposit:	10 August 2026
Date of Acceptance:	24 July 2026
Last Modified:	10 Aug 2026 09:45
URI:	https://orca.cardiff.ac.uk/id/eprint/188799

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