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- Synthetic tsunami waveform catalogs with kinematic constraintsPublication . Baptista, Maria Ana Carvalho Viana; Miranda, Jorge Miguel; Matias, Luis; Omira, RachidIn this study we present a comprehensive methodology to produce a synthetic tsunami waveform catalogue in the northeast Atlantic, east of the Azores islands. The method uses a synthetic earthquake catalogue compatible with plate kinematic constraints of the area. We use it to assess the tsunami hazard from the transcurrent boundary located between Iberia and the Azores, whose western part is known as the Gloria Fault. This study focuses only on earthquake-generated tsunamis. Moreover, we assume that the time and space distribution of the seismic events is known. To do this, we compute a synthetic earthquake catalogue including all fault parameters needed to characterize the seafloor deformation covering the time span of 20 000 years, which we consider long enough to ensure the representability of earthquake generation on this segment of the plate boundary. The computed time and space rupture distributions are made compatible with global kinematic plate models. We use the tsunami empirical Green's functions to efficiently compute the synthetic tsunami waveforms for the dataset of coastal locations, thus providing the basis for tsunami impact characterization. We present the results in the form of offshore wave heights for all coastal points in the dataset. Our results focus on the northeast Atlantic basin, showing that earthquake-induced tsunamis in the transcurrent segment of the Azores-Gibraltar plate boundary pose a minor threat to coastal areas north of Portugal and beyond the Strait of Gibraltar. However, in Morocco, the Azores, and the Madeira islands, we can expect wave heights between 0.6 and 0.8 m, leading to precautionary evacuation of coastal areas. The advantages of the method are its easy application to other regions and the low computation effort needed.
- Reply to comment on "Probabilistic Tsunami Hazard in the Northeast Atlantic From Near- and Far-Field Tectonic Sources'' by Fonseca (Pure and Applied Geophysics, 2016)Publication . Omira, Rachid; Matias, Luis; Baptista, Maria Ana Carvalho VianaThe recent events of the Indian Ocean 2004 and the Tohoku-Oki 2011 have brought to the fore the hazardous nature of the tsunami phenomenon. Consequently, understanding and quantifying the tsunami hazard have gained a significant interest from researchers worldwide. Traditionally, deterministic approach, based on the maximum credible event or the worst-case scenario, has been used to assess the tsunami hazard. However, the absence of a single comprehensive way to define this scenario makes the usefulness of the deterministic method limited (Geist and Lynett 2014). Probabilistic tsunami hazard assessment (PTHA), on the other hand, takes into consideration the contribution of multiple tsunamigenic sources to elaborate tsunami hazard maps. PTHA is now widely used in different tsunami-prone areas of the globe (Annaka et al. 2007; Thio et al. 2007; Sørensen et al. 2012; Yadav et al. 2013; Roshan et al. 2016). In the NE Atlantic, many efforts have been conducted in the aftermath of the Indian Ocean tsunami of 2004 to assess hazard posed by tsunamis. They mainly addressed the tsunami hazard through the deterministic approach with a particular focus on the coastal impact from the 1755-like event (Omira et al. 2010, 2011, 2013; Baptista et al. 2011). Alternatively, Omira et al. (2015) and, more recently, Omira et al. (2016) introduced the probabilistic tsunami hazard assessment in the NE Atlantic from sources of tectonic origin. We welcome the comment by Fonseca (2016) as it gives us the opportunity to better discuss the progress in the PTHA in the NE Atlantic. In his comment, Fonseca (2016) focuses on three main points: (1) the communication of the hazard; (2) the conservatism in the hazard analysis; (3) the uncertainty treatment. The reply to the comments raised by Fonseca (2016) will be addressed in the following sections.