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- Exploring offshore sediment evidence of the 1755 CE tsunami (Faro, Portugal): implications for the study of outer shelf tsunami depositsPublication . Kümmerer, Vincent; Drago, Teresa; Veiga-Pires, C.; Silva, Pedro; Magalhaes, Vitor; Mena, Anxo; Lopes, Ana; Rodrigues, Ana Isabel; Schmidt, Sabine; Terrinha, Pedro; Baptista, Maria AnaOuter shelf sedimentary records are promising for determining the recurrence intervals of tsunamis. However, compared to onshore deposits, offshore deposits are more difficult to access, and so far, studies of outer shelf tsunami deposits are scarce. Here, an example of studying these deposits is presented to infer implications for tsunami-related signatures in similar environments and potentially contribute to pre-historic tsunami event detections. A multidisciplinary approach was performed to detect the sedimentary imprints left by the 1755 CE tsunami in two cores, located in the southern Portuguese continental shelf at water depths of 58 and 91 m. Age models based on C-14 and Pb-210(xs) allowed a probable correspondence with the 1755 CE tsunami event. A multi-proxy approach, including sand composition, grain-size, inorganic geochemistry, magnetic susceptibility, and microtextural features on quartz grain surfaces, yielded evidence for a tsunami depositional signature, although only a subtle terrestrial signal is present. A low contribution of terrestrial material to outer shelf tsunami deposits calls for methodologies that reveal sedimentary structures linked to tsunami event hydrodynamics. Finally, a change in general sedimentation after the tsunami event might have influenced the signature of the 1755 CE tsunami in the outer shelf environment.
- A new tsunami runup predictorPublication . Wronna, Martin; Baptista, Maria Ana; Kanoglu, UtkuWe introduce a new parameter, tsunami runup predictor (TRP), relating the accelerating phase of the wave to the length of the beach slope over which the wave is travelling. We show the existence of a relationship between the TRP and the runup for different initial waveforms, i.e. leading elevation N-waves (LENs) and leading depression N-waves (LDNs). Then, we use the TRP to estimate tsunami runup for past tsunami events. The comparison of the runup estimates against field data gives promising results. Thus, the TRP provides first-order estimates of tsunami runup once the offshore waveform is known or estimated and, therefore, it could be beneficial to be implemented in tsunami early warning systems.
- The transoceanic 1755 Lisbon tsunami in MartiniquePublication . Roger, J.; Baptista, Maria Ana; Sahal, A.; Accary, F.; Allgeyer, S.; Hébert, H.On 1 November 1755, a major earthquake of estimated M (w)=8.5/9.0 destroyed Lisbon (Portugal) and was felt in the whole of western Europe. It generated a huge transoceanic tsunami that ravaged the coasts of Morocco, Portugal and Spain. Local extreme run-up heights were reported in some places such as Cape St Vincent (Portugal). Great waves were reported in the Madeira Islands, the Azores and as far as the Antilles (Caribbean Islands). An accurate search for historical data allowed us to find new (unpublished) information concerning the tsunami arrival and its consequences in several islands of the Lesser Antilles Arc. In some places, especially Martinique and the Guadeloupe islands, 3 m wave heights, inundation of low lands, and destruction of buildings and boats were reported (in some specific locations probably more enclined to wave amplification). In this study, we present the results of tsunami modeling for the 1755 event on the French island of Martinique, located in the Lesser Antilles Arc. High resolution bathymetric grids were prepared, including topographic data for the first tens of meters from the coastline, in order to model inundations on several sites of Martinique Island. In order to reproduce as well as possible the wave coastal propagation and amplification, the final grid was prepared taking into account the main coastal features and harbour structures. Model results are checked against historical data in terms of wave arrival, polarity, amplitude and period and they correlate well for Martinique. This study is a contribution to the evaluation of the tele-tsunami impact in the Caribbean Islands due to a source located offshore of Iberia and shows that an 8.5 magnitude earthquake located in the northeastern Atlantic is able to generate a tsunami that could impact the Caribbean Islands. This fact must be taken into account in hazard and risk studies for this area.
- Introduction to "Twenty Five Years of Modern Tsunami Science Following the 1992 Nicaragua and Flores Island Tsunamis, Volume II"Publication . Kanoglu, Utku; Tanioka, Yuichiro; Okal, Emile A.; Baptista, Maria Ana; Rabinovich, AlexanderFollowing the first volume (PAGEOPH, 2019, 176, No. 7), twenty-four papers on tsunamis are included in the PAGEOPH topical issue "Twenty five years of modern tsunami science following the 1992 Nicaragua and Flores Island tsunamis: Volume II,'' reporting on the frontiers of tsunami science and research. The first two papers overview meteorological tsunamis, discussing progress since the 1992 Daytona event, and examining the March 2017 Persian Gulf destructive event. The next four papers review historical tsunami events, starting with a paper providing statistics for the last 120 years. The 2018 Kodiak event is investigated in the following two papers. A set of five papers discusses tsunami-warning methodologies specifically for the Australia and Nankai (Japan) regions, and general tsunami warning approaches. Probabilistic tsunami hazard assessment including case studies for two Australian coasts and the Pacific Coast of Central America, as well as discussion regarding the effect of shallow slip amplification uncertainty, and tsunami hazard assessment for the Port of Ensenada, Baja California, are presented in the next five papers. Two papers discuss tsunami tide interaction, and the following two investigate landslide-generated tsunamis, specifically a tsunami landslide scenario study for the Maltese Islands, and the 1694 Ambon, Indonesia tsunami. Tsunami hydrodynamics studies investigating shoaling on steep continental slopes and transmission of long surface, and tsunami-like waves are presented in the last two papers.