A “cookbook” for probabilistic tsunami hazard and risk assessment

Probabilistic tsunami hazard and risk assessment methods (abbreviated PTHA and PTRA, respectively) have evolved quickly over the past 10 to 15 years. Given this rapidly evolving landscape, there is a need to establish best practices for PTHA and PTRA to improve reliability, comparability and reproducibility of studies applying such methods. The recently concluded Cost Action CA18109 AGITHAR (2019-2023) intended to improve the scientific foundation for PTHA and PTRA. To materialize the networking activities into guidelines and best practices, more than 50 tsunami scientists have joined forces to develop a so-called cookbook providing recommendations and workflows for both PTHA and PTRA. The cookbook will give an overview of existing methods, unify the descriptions of named workflows, make best practices examples available to a wider community, and provide background information to various stakeholder groups. We employ the analogy of a cookbook, because successful PTHA/PTRA workflows can be described by essential building blocks (ingredients) combined in specific ways (recipes) to serve the purpose of the analysis of actual application fields. In that regard, we first introduce the main ingredients in seven chapters describing e.g.  source models, tsunami models, vulnerability, exposure, as well as risk communication, and then present a series of recipes (25 in total) providing examples of how the ingredients can be combined in a workflow leading to a meaningful PTHA or PTRA. The cookbook can be used and read in different ways. On the one hand, and again in analogy to a usual cookbook, readers may browse through recipes, and access the ingredients chapters following the corresponding list of ingredients. The recipes all follow a similar organizational structure, so they can be accessed easily. On the other hand, the book can be read consecutively, starting with the study of ingredients, following the general workflow of PTHA and PTRA. By this, scholars will learn in a structured way how to build corresponding hazard and risk assessments. Finally, for the more experienced readers, the book may serve as a reference to the current state-of-the-art in this multidisciplinary research area. In this presentation, we will introduce the key ingredients described in the cookbook, as well as selected recipes. We will then summarize the main recommendations for future PTHA/PTRA studies, as provided in the book. The book is expected to be published in Autumn 2024.