| 03 Feb 2026
Basin-Scale Geometric Focusing: A Probabilistic-Geometric Framework for Global Tsunami Hazard Assessment and the 2025 Kamchatka Peninsula Tsunami
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 over 9,000 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 M8.8 Kamchatka Peninsula event. Validation against the 2025 M8.8 Kamchatka earthquake utilizes phase-corrected FUNWAVE-TVD simulations and in-situ DART observations. The resulting ray-based coastal focusing patterns display a substantial qualitative and quantitative spatial agreement (Spearman's ρ = 0.66) 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 coastal hotspots of transoceanic tsunami impact.
Review of the manuscript: “Basin-Scale Geometric Focusing: A Probabilistic-Geometric Framework for Global Tsunami Hazard Assessment and the 2025 Kamchatka Peninsula Tsunami”
Recommended decision: Major revisions
1. Summary of the manuscript
The manuscript proposes a hybrid probabilistic–geometric framework to identify coastal areas exposed to transoceanic tsunamis at global scale, combining Gutenberg–Richter-type seismic weighting with ray-tracing simulations. The central idea is to use ray density and coastal ray-termination points as a rapid proxy for bathymetry-induced focusing or shadowing. The approach is validated using the 2025 Kamchatka event through phase-corrected FUNWAVE-TVD simulations and comparison with DART and tide-gauge records. The work shows a reasonable spatial correlation between the geometric proxy and the maximum amplitudes obtained from the hydrodynamic model. The article is interesting and potentially useful as a rapid screening tool, although it still requires a more rigorous delimitation of its scope, of the probabilistic component, and of what can properly be referred to as “hazard assessment”.
2. Structure of the manuscript by sections
3. General comments
4. Main comment
My main concern is that the manuscript currently makes claims that are broader than what is demonstrated by the analysis. In its present form, the work reasonably validates a geometric proxy for transoceanic coastal exposure, but not a complete global probabilistic hazard framework. This distinction is important because it affects the title, the abstract, and the interpretation of the results. The authors should either substantially reinforce the probabilistic treatment and uncertainty quantification, or reformulate the scope of the manuscript as a global screening/prioritization tool for transoceanic tsunami exposure.
5. Specific comments
Lines 1–3 (title): There is a missing space in “AProbabilistic-Geometric”. In addition, the title is somewhat too ambitious. I suggest replacing “Global Tsunami Hazard Assessment” with “Global Tsunami Exposure Screening” or an equivalent formulation, unless the probabilistic component is substantially strengthened.
Lines 5–10 (abstract): The abstract works well overall, but it mixes “hazard”, “exposure”, and “coastal focusing patterns” as if they were equivalent. The authors should clarify from the outset what variable the ray model predicts and what it does not predict.
Lines 22–33: The exclusion of non-seismic tsunamis and nearshore processes is well motivated, for which decisions is the method suitable? And not?.
Lines 35–55: This part repeats the justification for ray tracing several times. It could be shortened considerably without losing content. The central argument is already clear from the references to Satake (1988) and Tehranirad et al. (2015).
Lines 61–75: The introduction of the probabilistic component is well placed, but a sentence is needed to clarify that λ is not a direct probability of coastal amplitude exceedance.
Lines 94–106: In Figure 1 and its caption, magnitude is described as being on the “Richter scale”. For large events, this should be revised and the appropriate magnitude scale should be used, most likely Mw. In addition, “AMagnitude of Completeness” requires typographical correction.
Lines 109–126: The construction of the curve Γ and the KDE is a delicate parts of the manuscript. how Γ is generated?,
Lines 184–191: The normalized ray termination count is used as a proxy for amplitude. This is a crucial assumption and deserves a more nuanced discussion. Is it a proxy for maximum amplitude, incident energy, or relative probability of impact?
Lines 230–240: The summary of the Kamchatka event includes information on impacts and damage that should be supported by specific references if retained.
Lines 284–303: The phase correction appears useful, but the current presentation mixes several elements (compressibility, elasticity, shortest path, and DART observations) in a dense block. I suggest separating more clearly the method, the data, and the result of the correction.
Lines 333–340: Spearman’s ρ = 0.66. How many coastal points are used? What is the statistical significance? Does it change if selected regions are excluded or if the coastal proximity criterion is modified?
6. Typos and local style improvements
Review spacing and typographical errors throughout the manuscript, including “large-scale ray-tracing”, “farfield”, “AMagnitude”, and “wether”.
Standardize the use of “far-field” and “near-field” throughout the text.
7. Final assessment
I recommend Major revisions. The manuscript presents an interesting and potentially useful probabilistic–geometric framework for the rapid identification of transoceanic tsunami focusing corridors. The combination of recurrence-based source weighting, ray tracing, FUNWAVE simulations, and observational comparison is valuable. However, the current framing is broader than what the analysis demonstrates. In particular, the manuscript should more clearly distinguish between probabilistic tsunami hazard assessment, exposure screening, and relative geometric focusing. The probabilistic component remains simplified, the uncertainty and sensitivity analysis is limited, and the validation relies mainly on one event and one principal spatial correlation metric. These issues affect the interpretation of the results and the claims made in the title, abstract, and conclusions. I consider major revision appropriate. The manuscript has clear potential if the scope is reframed and the methodological assumptions are better justified.