Mourad Bezzeghoud
Universidade de Évora, Physics Department, Faculty Member
- Full professor in Physics (Seismology), he worked on a diversity of topics, particularly on the source mechanism of e... moreFull professor in Physics (Seismology), he worked on a diversity of topics, particularly on the source mechanism of earthquakes, seismicity, crust deformation and seismotectonics of the Ibero-Maghrebian and Azores-Gibraltar regions. He is presently participating in research projects on earthquake seismology, seismotectonics, earth's crust structure, strong ground motion modelling, and seismic hazard along the Western part of the Eurasia-Nubia plate boundary.edit
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Research Interests: Geology and Geophysics
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... Centro de Geofísica de Évora e Departamento de Física da Universidade de Évora, R. Romão Ramalho, 59, 7000 Évora, mourad@ uevora. ... bem delimitado na parte oceânica, até ao banco de Gorringe, já, depois deste, na sua zona... more
... Centro de Geofísica de Évora e Departamento de Física da Universidade de Évora, R. Romão Ramalho, 59, 7000 Évora, mourad@ uevora. ... bem delimitado na parte oceânica, até ao banco de Gorringe, já, depois deste, na sua zona continental.(Ibéria-África) ela apresenta-se ...
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Geophysical data with noise issues are quite common, resulting in low detection conditions. This prevents the ground content from being evaluated to determine the existence of structures buried in the ground in an archaeological site.... more
Geophysical data with noise issues are quite common, resulting in low detection conditions. This prevents the ground content from being evaluated to determine the existence of structures buried in the ground in an archaeological site. Standard processing on ground-penetrating radar and magnetic data does not effectively eliminate or mitigate this effect. The use of advanced and customized data processing is a viable solution to the problem. This processing can be applied using mathematical transforms in conjunction with data decomposition techniques, allowing for easier and less computationally intensive data manipulation. The circular symmetry of the data is enabled by the 2D Fourier transform, making operations like filtering easier to implement. In the transformed domain, factoring techniques such as singular value decomposition can be used (SVD). After analyzing the decomposed signal, the components can be matched to the signal and noise. The 2D wavelet transform allows for data decomposition, with operations such as multiresolution SVD and multidirectional gradient calculation applied to each channel to select the most informative content from a dataset. The chain application of these operations allows for the improvement of geophysical data despite an apparent lack of information. Testing on field data obtained at Villa Romana de Pisões (Beja, Portugal) is an example of successful application. Advanced geophysical data processing operations can improve the data and should be used in conjunction with standard operations.Acknowledgment: The work was supported by the Portuguese Foundation for Science and Technology (FCT) project UIDB/04683/2020 - ICT (Institute of Earth Sciences).
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Research Interests: Geology and Seismology
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The Azores archipelago is a seismically active region composed of nine islands and located at the triple junction of the American, Nubian, and Eurasian plates. Since its settlement in the fifteenth century, 33 earthquakes with intensity... more
The Azores archipelago is a seismically active region composed of nine islands and located at the triple junction of the American, Nubian, and Eurasian plates. Since its settlement in the fifteenth century, 33 earthquakes with intensity higher than VII have been reported. This article shows areas that experienced strong ground shaking using maximum observed intensity (MOI) mapping. For this purpose, 323 records from 167 earthquakes in the period 1522–2012 have been compiled, and MOI values are interpolated on a regular grid of points using the kriging method. The comparison of observed and calculated MOI for four damaging and deadly earthquakes indicates a good calibration of the procedure relative to the available dataset. For the islands of the central group, which comprises Terceira, Graciosa, Sao Jorge, Pico, and Faial, the highest calculated intensities (XI) are located in the eastern part of Sao Jorge Island. Intensities (X) are observed on Faial along a northwest–southeast stripe. For Graciosa, Terceira, and Pico, the estimated maximum intensities are IX, VIII, and VII, respectively. For the eastern group of islands, the highest intensities (X) are located in the southeastern part of Sao Miguel Island, and on Santa Maria Island the maximum intensity of VI is observed in its eastern part. Finally, Flores and Corvo Islands, located on the American plate, have a very low seismicity.
Research Interests: Geology, Geophysics, Seismology, Plate Tectonics, Earthquakes, and 3 moreAzores, Archipelago, and Catalogs
O estudo da sismicidade em Portugal ao longo de várias centenas de anos é essencial para uma melhor avaliação do risco sísmico ao qual o continente está sujeito. Neste trabalho, a organização de diversas fontes históricas e atuais numa... more
O estudo da sismicidade em Portugal ao longo de várias centenas de anos é essencial para uma melhor avaliação do risco sísmico ao qual o continente está sujeito. Neste trabalho, a organização de diversas fontes históricas e atuais numa base de dados possibilita validar facilmente a ocorrência de eventos sísmicos no período desde 1300 a 2014. A construção de um mapa de intensidades máximas observadas neste período permite mostrar que todo o território Português esteve sujeito a sismos com Io≥V. Existem também registos de grandes eventos sísmicos, concentrados em pequenas áreas, que causaram danos consideráveis. De destacar ainda o impacto dos sismos com epicentro no mar, nas cidades costeiras, no Centro e Sul do país
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Portugal, located in the southwest region of the Eurasian plate, has been affected by several destructive earthquakes throughout its history, the most well-known being the 1755 Great Lisbon earthquake. The seismicity of the territory,... more
Portugal, located in the southwest region of the Eurasian plate, has been affected by several destructive earthquakes throughout its history, the most well-known being the 1755 Great Lisbon earthquake. The seismicity of the territory, both in the mainland and in the Azores and Madeira islands, has prompted the continuous development of seismic monitoring, from the first known macroseismic inquiry, following the 1755 Great Lisbon earthquake, to the current state-of-the-art seismic network. Once scattered in separate efforts, at present, most seismic stations in Portugal relay its data to a common data center, at Instituto Português do Mar e da Atmosfera, where data are automatically processed for the downstream generation of both manually revised and automatically generated products and services. In this article, we summarize the evolution of the permanent seismic network, its current status, the products and services that are publicly available, a recent effort of rapid deployment o...
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Temporary seismic stations were quickly deployed after the mainshock (first station was installed 1h30 after the mainshock) , as a collaborative effort between ICT (Instituto de Ciências da Terra, Évora) and IDL (Instituto Dom Luiz). The... more
Temporary seismic stations were quickly deployed after the mainshock (first station was installed 1h30 after the mainshock) , as a collaborative effort between ICT (Instituto de Ciências da Terra, Évora) and IDL (Instituto Dom Luiz). The full deployment encompassed 14 broadband stations (CMG 6TD, 30 s) and 21 short-period stations (CDJ, 2.0 Hz). The 35 stations, deployed around the epicentral area, together with the backbone permanent seismic network, allow a unique study of microseismic activity during this crisis.
Research Interests: Geology and Seismology
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In this work all available fault plane solutions, of the shallow depth seismic events with 1.9 _ M _ 8.0 occurred in the period 1960-2003 in continental Portugal and adjacent margin, have been collected, carefully checked and analysed.... more
In this work all available fault plane solutions, of the shallow depth seismic events with 1.9 _ M _ 8.0 occurred in the period 1960-2003 in continental Portugal and adjacent margin, have been collected, carefully checked and analysed. The distribution of the focal mechanisms have been analysed in detail, by means of different techniques, projections and graphic representations. In first analysis, these focal mechanisms present an accentuated variability (strike-slip, inverse and oblique); however, we have identified some important patterns in the following regions: west Portuguese margin (strike-slip), Lisbon and Vale do Tejo (dip-slip), region of Evora and vicinity (strike-slip), region of Algarve (strike-slip) and inter-plates boundary zone (reverse). The geographical distribution of the horizontal projection of the axes P and T show that the orientation of the axes P is NW – SE to NNW – SSE from horizontal to sub-horizontal inclination while the axes T presents an inclination th...
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The seismicity of the Tell Atlas, which extends from the Algerian margin to the South Atlasic fault system, is related to the dynamics of Quaternary basins under an oblique NW–SE convergent stress regime, including the basins of Mleta and... more
The seismicity of the Tell Atlas, which extends from the Algerian margin to the South Atlasic fault system, is related to the dynamics of Quaternary basins under an oblique NW–SE convergent stress regime, including the basins of Mleta and L’Habra in the west, Cheliff and Mitidja in the centre, and Soummam, Hodna and Guelma in the east. This seismicity is characterized by moderate to low magnitudes with strong events occurring generally once a decade. Over the last six decades, several moderate, strong and major events occurred that were associated with extensive and severe damage, such as those of El Asnam (1954, Ms 6.7; 1980, Ms 7.3), Constantine (1985, Ms 6.0), Tipasa–Chenoua (1989, Ms 6.0), Mascara (1994, Ms 6.0), Ain Temouchent (1999, Ms 5.8), Beni Ouartilane (2001, Ms 5.6), Zemmouri—Boumerdes (2003, Mw 6.8) and Laalam (2005, Ms 5.8), in addition to numerous large historical seismic events, including those that occurred in Algiers (1365 and 1716, Io = X), Oran (1790, Io = X), Mascara (1819, Io = X), Djidjelli (1856, Io = VIII) and M’sila (1885, Io = IX). This chapter presents a review of the seismicity of North Algeria and a detailed analysis of the main earthquakes that have occurred in the Tell Atlas since 1980. Finally, the impacts of several significant earthquakes that occurred during the period between 1364 and 2015 are presented and discussed in terms of seismic energy.
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The Azores archipelago is a seismically active region composed of nine islands and located at the triple junction of the American, Nubian, and Eurasian plates. Since its settlement in the fifteenth century, 33 earthquakes with intensity... more
The Azores archipelago is a seismically active region composed of nine islands and located at the triple junction of the American, Nubian, and Eurasian plates. Since its settlement in the fifteenth century, 33 earthquakes with intensity higher than VII have been reported. This article shows areas that experienced strong ground shaking using maximum observed intensity (MOI) mapping. For this purpose, 323 records from 167 earthquakes in the period 1522–2012 have been compiled, and MOI values are interpolated on a regular grid of points using the kriging method. The comparison of observed and calculated MOI for four damaging and deadly earthquakes indicates a good calibration of the procedure relative to the available dataset. For the islands of the central group, which comprises Terceira, Graciosa, Sao Jorge, Pico, and Faial, the highest calculated intensities (XI) are located in the eastern part of Sao Jorge Island. Intensities (X) are observed on Faial along a northwest–southeast stripe. For Graciosa, Terceira, and Pico, the estimated maximum intensities are IX, VIII, and VII, respectively. For the eastern group of islands, the highest intensities (X) are located in the southeastern part of Sao Miguel Island, and on Santa Maria Island the maximum intensity of VI is observed in its eastern part. Finally, Flores and Corvo Islands, located on the American plate, have a very low seismicity.
Research Interests: Geology, Geophysics, Seismology, Plate Tectonics, Earthquakes, and 3 moreAzores, Archipelago, and Catalogs
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ABSTRACT
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ABSTRACT