NGI researchers are central to the new international tsunami handbook
Five NGI researchers have contributed to a new international handbook that sets the standard for how the world calculates tsunami hazard and risk. The book is freely available for download.
How the “tsunami book” was created: The authors discuss the development of a practical guide to tsunami risk at a meeting in the AGITHAR research network in Málaga in 2022. The aim was to turn advanced calculations and models into knowledge that can actually be used to make coastal communities safer. ( Photo: AGITHAR)
The newly released Probabilistic Tsunami Hazard and Risk Analysis: A Cookbook brings together 68 researchers from around the world. From NGI, senior researchers Finn Løvholt, Carl B. Harbitz, Sylfest Glimsdal, Naveen Ragu Ramalingam and Steven J. Gibbons have contributed to the work.
Finn Løvholt is one of the book's eight editors and has been central to the development of several chapters.
"This book represents the scientific foundation on which we are building the Global Tsunami Model. By providing transparent, standardised methods, we aim to support better-informed decisions that ultimately reduce risk and strengthen resilience in coastal communities worldwide," says Løvholt.
From worst-case to probability
Traditionally, tsunami assessments have relied on single scenarios representing worst-case outcomes. The probabilistic approach is different: instead of simulating a single event, researchers run thousands of simulations covering the full spectrum of possible tsunamis.
"A worst-case scenario can be a useful tool for specific applications, yet it is important to be aware that it tells you nothing about probability. You don't know if it occurs once in a century or once in a thousand years," explains Stefano Lorito, editor and board member of the Global Tsunami Model.
Norwegian fjords as a case study
The book contains 25 detailed "recipes" showing how the methods can be applied in practice. One of these addresses a previous tsunami hazard from landslides in Norwegian fjords, using the Lyngen area as an example. Løvholt and Glimsdal wrote this recipe.
"We wanted the book to show how state-of-the-art methods can be applied to real examples. This can support better decisions on land-use planning, building codes, and evacuation routes in coastal areas worldwide," says Finn Løvholt.
The book is the result of the COST Action AGITHAR network, which involved over 150 tsunami experts between 2019 and 2023. The network was established as a catalyst for the development of the Global Tsunami Model.
