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

• Published in: Frontiers in Earth Science
• Main Authors: Roberto Basili, Beatriz Brizuela, André 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, Roberto Tonini, Manuela Volpe, Sylfest Glimsdal, Carl Bonnevie Harbitz, Finn Løvholt, Maria Ana Baptista, Fernando Carrilho, Luis Manuel Matias, Rachid Omira, Andrey Babeyko, Andreas Hoechner, Mücahit Gürbüz, Onur Pekcan, Ahmet Yalçıner, Miquel Canals, Galderic Lastras, Apostolos Agalos, Gerassimos Papadopoulos, Ioanna Triantafyllou, Sabah Benchekroun, Hedi Agrebi Jaouadi, Samir Ben Abdallah, Atef Bouallegue, Hassene Hamdi, Foued Oueslati, Alessandro Amato, Alberto Armigliato, Jörn Behrens, Gareth Davies, Daniela Di Bucci, Mauro Dolce, Eric Geist, Jose Manuel Gonzalez Vida
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2021
• Subjects: probabilistic tsunami hazard assessment; earthquake-generated tsunami; hazard uncertainty analysis; ensemble modeling; maximum inundation height; NEAM; Science; Q; North East Atlantic
• Online Access: https://doi.org/10.3389/feart.2020.616594; https://doaj.org/article/b7d857ac818948dfaddd9e270fe33b44

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 ...