Rachid Omira

Rachid Omira
University of Lisbon | UL · Instituto Geofísico do Infante D. Luiz

PhD. in Geophysics

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103
Publications
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Publications

Publications (103)
Article
Full-text available
The Yellow Sea is recognized as a meteotsunami “hot-spot”, with a relatively high rate of events’ occurrence. The March 2007 and May 2008 meteotsunami events attracted large attention due to their deadly and high impact on the west coast of the Korean Peninsula. However, other small size meteotsunamis remain less known because of their insignifican...
Article
Full-text available
Volcanoes can produce tsunamis through earthquakes, caldera and flank collapses, pyroclastic flows, or underwater explosions1,2,3,4. These mechanisms rarely displace enough water to trigger transoceanic tsunamis. Violent volcanic explosions, however, can cause global tsunamis1,5 by triggering acoustic-gravity waves6,7,8 that excite the atmosphere-o...
Article
This paper investigates the deterministic tsunami hazard scenarios to assess the potential impact on the Qurayyat coast, northeast Oman. It assesses the maximum tsunami hazard characteristics with a focus on the zoning of tsunami hazard related to the human ability to stand within the inundation areas. Additionally, probabilities of buildings damag...
Article
Full-text available
Tsunamis constitute a significant hazard for European coastal populations, and the impact of tsunami events worldwide can extend well beyond the coastal regions directly affected. Understanding the complex mechanisms of tsunami generation, propagation, and inundation, as well as managing the tsunami risk, requires multidisciplinary research and inf...
Article
This work addresses the transatlantic impact of the 1755 CE Lisbon tsunami on the Brazilian coast using historical description, numerical modeling and sediment analysis. Historical documents are revisited, novel numerical modeling is provided and coupled with sedimentological data. The combination of these results attests to the potential presence...
Article
Mass-wasting events are a key process in the evolution of volcanic ocean islands. They occur at various dimensional scales and present a major source of hazard. When the collapsed material plunges into the sea, destructive tsunamis can be generated. Yet, the hazard potential of collapse-induced tsunamis is still poorly understood with different opi...
Article
Submarine landslides are a ubiquitous geohazard in the marine environment and occur at multiple scales. Increasing efforts have been made during the last decade to catalogue and categorise submarine landslides in comprehensive databases, aiming to better understand their preconditioning and trigger factors. Using the recently compiled, open-access...
Preprint
The Yellow Sea is recognized as a meteotsunami “hot-spot”, with a relatively high rate of events’ occurrence. The March 2007 and May 2008 meteotsunami events attracted large attention due to their deadly and high impact on the west coast of the Korean Peninsula. However, other small size meteotsunamis remain less known because of their insignifican...
Article
Full-text available
Recent developments in optical fiber cable technology allows the use of existing and future submarine telecommunication cables to provide seismic and sea-level information. In this work we study the impact of three different technologies, 1) SMART, Science Monitoring and Reliable Telecommunications; 2) DAS, Distributed Acoustic Sensing, and; 3) LI,...
Article
Full-text available
Submarine landslides are major geohazards occurring on distinct seabed domains ranging from shallow coastal areas to the deeper points of the ocean. The nature and relief of the seabed are key factors influencing the location and size of submarine landslides. Efforts have recently been made to compile databases of submarine landslide distribution a...
Article
Destructive tsunamis were reported in the Oman Sea after large earthquakes. The Northern Sultanate of Oman and United Arab Emirates (UAE) were subjected to two confirmed tsunamis on 27 November 1945, caused by an Mw 8.1 earthquake in Makran subduction zone, and on 24 September 2013 following the Mw 7.7 Baluchistan earthquake. In this study, determi...
Article
Full-text available
Tsunami hazard can be analyzed from both deterministic and probabilistic points of view. The deterministic approach is based on a “credible” worst case tsunami, which is often selected from historical events in the region of study. Within the probabilistic approach (PTHA, Probabilistic Tsunami Hazard Analysis), statistical analysis can be carried o...
Article
Seamounts are spectacular bathymetric features common within volcanic and tectonically active continental margins. During their lifecycles, they evolve through stages of construction and destruction. The latter are marked by variable magnitude flank collapses that often interrupt the evolution of seamounts and constitute a major source of hazard. T...
Article
Full-text available
On 6 and 7 July 2010, uncommon sea waves were observed along the coast of Portugal. The Portuguese tide gauge network recorded the sea-level signals showing tsunami-like waves of heights varying from 0.14 to 0.6 m (crest-to-trough) and of periods in the range of 30 to 60 min. Analysis of both oceanic and atmospheric data revealed the occurrence of...
Article
Full-text available
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 calculati...
Preprint
Full-text available
Submarine landslides are major geohazards occurring on distinct seabed domains ranging from shallow coastal areas to the deeper points of the ocean. The nature and relief of the seabed are key factors influencing the location and size of submarine landslides. Efforts have recently been made to compile databases of submarine landslide distribution a...
Article
Full-text available
On December 22, 2018, a sector of the Anak Krakatau volcano edifice collapsed into the sea, generating a tsunami that hit the Sunda Strait coasts in Indonesia. The collapse followed a period of 6 months of volcanic activity that was insufficient to warn the tsunami-threatened coastal population. The Anak Krakatau tsunami resulted in hundreds of cas...
Article
Full-text available
In this study, we present a linear inverse approach for the computation of the initial water displacement of a tsunami. The method uses empirical Green functions and linear shallow water wave theory. We apply this methodology to study the source of the 24 September 2013 tsunami off the Makran coast. We re-analyze the 2013 tsunami data, particularly...
Conference Paper
Full-text available
Submarine mass-failures are recognized worldwide as a potential source of marine geo-hazards. They can compromise the safety and integrity of seafloor and subsurface infrastructures through destroying offshore installations or triggering potential tsunamis. This applies to the SW Iberia Margin, where the occurrence of damaging and tsunamigenic unde...
Conference Paper
Full-text available
Submarine landslides are common features occurring on the flanks of seamounts. Often triggered by earthquakes or volcanic activity, such landslides are potential generators of tsunamis that constitute a dire geohazard for coastal communities. Understanding the recurrence history and geomorphology of seamount-flanking landslides and their link to se...
Article
Full-text available
Regional and global tsunami hazard analysis requires simplified and efficient methods for estimating the tsunami inundation height and its related uncertainty. One such approach is the amplification factor (AF) method. Amplification factors describe the relation between offshore wave height and the maximum inundation height, as predicted by lineari...
Article
The stratigraphy of the Tagus river ebb-tidal delta off Lisbon (Portugal) is investigated using high resolution multichannel seismic reflection profiles with the purpose of searching for sedimentary or erosive features associated with landslides. The Tagus delta is sub-divided in two prograding seismic units of 17 ky to 13 ky and 13 ky to Present b...
Article
Full-text available
On September 28th, 2018, a powerful earthquake (Mw 7.5) struck the Island of Sulawesi in Indonesia. The earthquake was followed by a destructive and deadly tsunami that hit the Bay of Palu. A UNESCO international tsunami survey team responded to the disaster and surveyed 125 km of coastline along the Palu Bay up to the earthquake epicentre region....
Article
Full-text available
Numerical modelling is a fundamental tool for scenario-based evaluation of hazardous phenomena such as tsunami. Nevertheless, the numerical prediction highly depends on the tool quality and therefore the design of efficient numerical schemes that provide robust and accurate solutions still receives considerable attention. In this paper, we implemen...
Article
Full-text available
Abstract Tsunamis generated along the Makran subduction zone (MSZ) threaten the Sur coast of Oman, according to deterministic and probabilistic analyses presented here. A validated shallow water numerical code simulates the source-to-coast propagation and quantifies the coastal hazard in terms of maximum water level, flow depth, and inundation dist...
Conference Paper
Full-text available
The Moroccan Atlantic coast, opened on the tsunamigenic zone of the Gulf of Cadiz, is one of the areas largely impacted by the AD 1755 tsunami. Previous works simulating tsunami propagation and inundation along the Moroccan coast has been carried out. However, only few studies have addressed the effects of tidal variations on tsunami coastal impact...
Article
Full-text available
Background The Atlantic Coast of Morocco is prone to tsunami inundation. Therefore, in this region, earthquake-induced tsunami hazard has been intensively investigated leading to the development of a number of coastal inundation models. However, tsunami vulnerability remains not well understood to the same extent as the hazard. In this study, we us...
Article
Full-text available
Applying probabilistic methods to infrequent but devastating natural events is intrinsically challenging. For tsunami analyses, a suite of geophysical assessments should be in principle evaluated because of the different causes generating tsunamis (earthquakes, landslides, volcanic activity, meteorological events, asteroid impacts) with varying mea...
Poster
Full-text available
Record of transatlantic tsunamis are uncommon which is in contrast with the Pacific region. However, the AD 1755 Lisbon tsunami affected areas across the North Atlantic and the Caribbean (Roy et al, 2009). Recent historical research based on the colonial archives (Arquivo Histórico Ultramarino) (Veloso, 2015) have reported the impact of the AD 1755...
Article
Full-text available
In 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...
Chapter
Tsunamis occur quite frequently following large magnitude earthquakes along the Chilean coast. Most of these earthquakes occur along the Peru–Chile Trench, one of the most seismically active subduction zones of the world. This study aims to understand better the characteristics of the tsunamis triggered along the Peru–Chile Trench. We investigate t...
Conference Paper
Full-text available
The risk mitigation associated with tsunami events needs robust and accurate numerical tools to provide realistic solutions. We propose a comparative study between the efficiency of a finite volume numerical code, with second-order discretization in space and time, equipped with two different techniques to solve the non-conservative shallow-water e...
Presentation
Full-text available
The risk mitigation associated with tsunami events needs robust and accurate numerical tools to provide realistic solutions. We propose a comparative study between the efficiency of a finite volume numerical code, with second-order discretization in space and time, equipped with two different techniques to solve the non-conservative shallow-water e...
Article
Full-text available
In this study we present a comprehensive methodology to produce a synthetic tsunami waveform catalogue in the North East 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...
Article
Full-text available
Contributions of Geographical Sciences to Tsunami Risk Prevention in Morocco By focusing on Morocco, this article shows how the geographical sciences can contribute to improving the knowledge of tsunami risk and its prevention following an integrated and spatial approach based on the concept of scenario. The main results presented here come from t...
Article
Full-text available
Tsunami is among the most devastating natural hazards phenomenon responsible for significant loss of life and property throughout history. The Sultanate of Oman and United Arab Emirates are among the Indian Ocean countries that were subjected to one confirmed tsunami in November 27, 1945 due to an Mw 8.1 earthquake in Makran Subduction Zone. In thi...
Conference Paper
Full-text available
Moscone South ­ Poster Hall The NE Atlantic (NEA) is prone to tsunami impact of tectonic origin. Previous studies and tsunami catalogs report the occurrence of significant events namely the 1 November 1755 and the 28 February 1969. In the NEA, the most impacted areas are the coastal zone of Portugal, Morocco and the Cadiz Gulf in Spain. In this stu...
Article
Full-text available
This study constitutes a preliminary assessment of probabilistic tsunami inundation in the NE Atlantic region. We developed an event-tree approach to calculate the likelihood of tsunami flood occurrence and exceedance of a specific near-shore wave height for a given exposure time. Only tsunamis of tectonic origin are considered here, taking into ac...
Chapter
This chapter focuses on the first quantitative study of tsunami hazard in the Azores with numerical modeling, used to investigate the biggest failure known there to date. The numerical modeling is used to simulate its mass flow toward and under the sea, and the subsequent tsunami generation and propagation. The results suggest how both the present-...
Article
The Sultanate of Oman is among the Indian Ocean countries that were subjected to at least two confirmed tsunamis during the twentieth and twenty-first centuries: the 1945 tsunami due to an earthquake in the Makran subduction zone in the Sea of Oman (near-regional field tsunami) and the Indian Ocean tsunami in 2004, caused by an earthquake from the...
Article
The Sultanate of Oman is among the Indian Ocean countries that were subjected to at least two confirmed tsunamis during the twentieth and twenty-first centuries: the 1945 tsunami due to an earthquake in the Makran subduction zone in the Sea of Oman (near-regional field tsunami) and the Indian Ocean tsunami in 2004, caused by an earthquake from the...
Article
Full-text available
On 8 May 1939, an earthquake (Ms7.1) occurred near the Azores archipelago, with an epicentre located close to the western end of the Gloria fault. Previous studies present different epicentre locations spreading over a large area, and two different types of focal mechanisms. Given these uncertainties, the interpretation of the seismological informa...
Chapter
This study constitutes a preliminary assessment of probabilistic tsunami inundation in the NE Atlantic region. We developed an event-tree approach to calculate the likelihood of tsunami flood occurrence and exceedance of a specific near-shore wave height for a given exposure time. Only tsunamis of tectonic origin are considered here, taking into ac...
Article
Submarine mass failures represent one of the most significant marine geo-hazards. Their importance as a major contributor to tsunami generation and hazard has been recognized over the last 20–30 years. This study investigates a newly mapped submarine landslide, the South Hirondelle Landslide (SHL), and its potential to generate a tsunami and to thr...
Article
Full-text available
Tsunamis occur quite frequently following large magnitude earthquakes along the Chilean coast. Most of these earthquakes occur along the Peru–Chile Trench, one of the most seismically active subduction zones of the world. This study aims to understand better the characteristics of the tsunamis triggered along the Peru–Chile Trench. We investigate t...
Conference Paper
Full-text available
Les Tsunamis : éTaT des connaissances eT risques pour Le maroc résumé : Le tsunami du 26 décembre 2004 et le nombre considérable des victimes qu'il a causé a été à l'origine d'une prise en conscience générale des scientifiques et des politiciens sur ce type de risques en raison de la forte concentration de la population mondiale et des infrastructu...
Technical Report
Full-text available
This report focuses on large scale accessibility mapping and evacuation simulations of the ASTARTE test sites. It presents the main results achieved in the Task 9.4 of the WP9. The aim of this task is to provide operatives with scenario-based tools and solutions to develop evacuation plans for local communities. The hazard scenarios were based on t...
Conference Paper
Full-text available
Coastal areas in the North of Morocco are at risk of tsunami inundation. Overland tsunami propagation leads to widespread and dramatic changes in coastal morphology due to sediments erosion, transport and deposition processes. Tsunami sediments transport and morphological changes must take into consideration bed-load and suspended load transport of...
Article
Full-text available
In this paper, we present a deterministic approach to tsunami hazard assessment for the city and harbour of Sines, Portugal, one of the test sites of project ASTARTE (Assessment, STrategy And Risk Reduction for Tsunamis in Europe). Sines has one of the most important deep-water ports, which has oil-bearing, petrochemical, liquid-bulk, coal, and con...
Article
Full-text available
This paper is a contribution to a better understanding of the tsunamigenic potential of large submarine earthquakes. Here, we analyze the tsunamigenic potential of large earthquakes which have occurred worldwide with magnitudes around Mw 7.0 and greater during a period of 1 year, from June 2013 to June 2014. The analysis involves earthquake model e...
Conference Paper
Full-text available
Se presenta un síntesis de los trabajos sobre del riesgo de tsunami para las costas marroquíes, especialmente la fachada atlántica que el país comparte con Portugal y España. Se examinan los datos historicos disponibles que mayoritariamente corresponden al terremoto de 1755, y la repartición de los depósitos atribuidos a tsunamis a lo largo de la c...
Conference Paper
Full-text available
Tsunamis are low frequency but high impact natural disasters. The NE Atlantic coast seems to be among the less tsunami threatened zones. Recent studies show that most destructive tsunamis in the NE Atlantic were generated by earthquakes located in the South West Iberian Margin (SWIM), such as the November, 1st, 1755 Lisbon Earthquake (8,75Mw), whic...