A sub-asymptotic model for bivariate threshold exceedances

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Hauptverfasser: Lescart, Mirco, Kiriliouk, Anna, Naveau, Philippe
Format: Preprint
Veröffentlicht: 2026
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author Lescart, Mirco
Kiriliouk, Anna
Naveau, Philippe
author_facet Lescart, Mirco
Kiriliouk, Anna
Naveau, Philippe
contents Extreme value theory offers a statistical framework for quantifying the risk of rare events, with the generalized Pareto (GP) distribution providing the canonical limit model for univariate threshold exceedances. In many applications, however, extremes are intrinsically multivariate, requiring models that capture both marginal tail behaviours and joint extremal dependencies. Under asymptotic dependence, the multivariate GP distribution represents a suitable modelling family, but when asymptotic independence arises, sub-asymptotic models are needed. In this work, we propose and study a flexible sub-asymptotic parametric class to model bivariate threshold exceedances. Our new model accommodates a broad range of tail dependence behaviours and contains the standardised multivariate GP distribution as a limiting case while retaining margins that converge to univariate GP tails. Our formulation allows extremal dependence to evolve naturally with the marginal parameters on the original data scale, facilitating direct computation and interpretation of failure probabilities. Model inference is done via a likelihood-free neural Bayes estimation approach, with tailored prior specifications. An extensive simulation study and an application to Belgian rainfall extremes illustrate the estimation framework and the flexibility of the model.
format Preprint
id arxiv_https___arxiv_org_abs_2604_12405
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A sub-asymptotic model for bivariate threshold exceedances
Lescart, Mirco
Kiriliouk, Anna
Naveau, Philippe
Methodology
62G32, 62P12, 62F15
Extreme value theory offers a statistical framework for quantifying the risk of rare events, with the generalized Pareto (GP) distribution providing the canonical limit model for univariate threshold exceedances. In many applications, however, extremes are intrinsically multivariate, requiring models that capture both marginal tail behaviours and joint extremal dependencies. Under asymptotic dependence, the multivariate GP distribution represents a suitable modelling family, but when asymptotic independence arises, sub-asymptotic models are needed. In this work, we propose and study a flexible sub-asymptotic parametric class to model bivariate threshold exceedances. Our new model accommodates a broad range of tail dependence behaviours and contains the standardised multivariate GP distribution as a limiting case while retaining margins that converge to univariate GP tails. Our formulation allows extremal dependence to evolve naturally with the marginal parameters on the original data scale, facilitating direct computation and interpretation of failure probabilities. Model inference is done via a likelihood-free neural Bayes estimation approach, with tailored prior specifications. An extensive simulation study and an application to Belgian rainfall extremes illustrate the estimation framework and the flexibility of the model.
title A sub-asymptotic model for bivariate threshold exceedances
topic Methodology
62G32, 62P12, 62F15
url https://arxiv.org/abs/2604.12405