Skip to main content
U.S. flag

An official website of the United States government

The making of the NEAM Tsunami Hazard Model 2018 (NEAMTHM18)

March 5, 2021

The NEAM Tsunami Hazard Model 2018 (NEAMTHM18) is a probabilistic hazard model for tsunamis generated by earthquakes. It covers the coastlines of the North-eastern Atlantic, the Mediterranean, and connected seas (NEAM). NEAMTHM18 was designed as a three-phase project. The first two phases were dedicated to the model development and hazard calculations, following a formalized decision-making process based on a multiple-expert protocol. The third phase was dedicated to documentation and dissemination. The hazard assessment workflow was structured in Steps and Levels. There are four Steps: Step-1) probabilistic earthquake model; Step-2) tsunami generation and modeling in deep water; Step-3) shoaling and inundation; Step-4) hazard aggregation and uncertainty quantification. Each Step includes a different number of Levels. Level-0 always describes the input data; the other Levels describe the intermediate results needed to proceed from one Step to another. Alternative datasets and models were considered in the implementation. The epistemic hazard uncertainty was quantified through an ensemble modeling technique accounting for alternative models’ weights and yielding a distribution of hazard curves represented by the mean and various percentiles. Hazard curves were calculated at 2,343 Points of Interest (POI) distributed at an average spacing of ∼20 km. Precalculated probability maps for five maximum inundation heights (MIH) and hazard intensity maps for five average return periods (ARP) were produced from hazard curves. In the entire NEAM Region, MIHs of several meters are rare but not impossible. Considering a 2% probability of exceedance in 50 years (ARP≈2,475 years), the POIs with MIH >5 m are fewer than 1% and are all in the Mediterranean on Libya, Egypt, Cyprus, and Greece coasts. In the North-East Atlantic, POIs with MIH >3 m are on the coasts of Mauritania and Gulf of Cadiz. Overall, 30% of the POIs have MIH >1 m. NEAMTHM18 results and documentation are available through the TSUMAPS-NEAM project website (, featuring an interactive web mapper. Although the NEAMTHM18 cannot substitute in-depth analyses at local scales, it represents the first action to start local and more detailed hazard and risk assessments and contributes to designing evacuation maps for tsunami early warning.

Publication Year 2021
Title The making of the NEAM Tsunami Hazard Model 2018 (NEAMTHM18)
DOI 10.3389/feart.2020.616594
Authors Roberto Basili, Beatriz Brizuela, Andre Herrero, Sarfraz Iqbal, Stefano Lorito, Francesco Emanuele Maesano, Shane Murphy, Paolo Perfetti, Fabrizio Romano, Antonio Scala, Jacopo Selva, Matteo Taroni, Mara Monica Tiberti, Hong Kie Thio, R. Tonini, Manuela Volpe, Sylfest Glimsdal, Carl B. Harbitz, Finn Lovholt, Maria Ana Baptista, Fernando Carrilho, Luis M. A. Matias, Rachid Omira, Andrey Babeyko, Andreas Hoechner, Mucahit Gurbuz, Onur Pekcan, A. Yalciner, Miquel Canals, Galderic Lastras, Apostolos Agalos, Gerassimo Papadapoulos, Ioanna Triantafyllou, Sabah Benchekroun, Hedi Agrebi Jaouadi, Samir Ben Abdallah, Atef Bouallegue, Hassene Hamdi, Foued Oueslati, A. Amato, Alberto Armigliato, Jörn Behrens, Gareth Davies, Daniela Di Bucci, Mauro Dolce, Eric L. Geist, Jose Manuel Gonzalez Vida, Mauricio Gonzalez, Jorges Macias Sanchez, C. Meletti, Ceren Ozer Sozdinler, Marco Pagani, Tom Parsons, Jascha Polet, William Power, Mathilde B. Sorensen, Andrey Zaytsev
Publication Type Article
Publication Subtype Journal Article
Series Title Frontiers in Earth Science
Index ID 70218813
Record Source USGS Publications Warehouse
USGS Organization Pacific Coastal and Marine Science Center