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The COVID-19 pandemic has caused chaos in many sectors and industries. In the energy sector, the demand has fallen drastically during the first quarter of 2020. The University of Almeria campus also declined the energy consumption in 2020, and through this study, we aimed to measure the impact of closing the campus on the energy use of its different facilities. We built our analysis based upon the dataset collected during the year 2020 and previous years; the patterns evolution through time allowed us to better understand the energy performance of each facility during this exceptional year. We rearranged the university buildings into categories, and all the categories reduced their electricity consumption share in comparison with the previous year of 2019. Furthermore, the portfolio of categories presented a wide range of ratios that varied from 56% to 98%, the library category was found to be the most influenced, and the research category was found to be the least influenced. This opened questions like why some facilities were influenced more than others? What can we do to reduce the energy use even more when the facilities are closed? The university buildings presented diverse structures that revealed differences in energy performance, which explained why the impact of such an event (COVID-19 pandemic) is not necessarily relevant to have equivalent variations. Nevertheless, some management deficiencies were detected, and some energy savings measures were proposed to achieve a minimum waste of energy.
Mehdi Chihib; Esther Salmerón-Manzano; Mimoun Chourak; Alberto-Jesus Perea-Moreno; Francisco Manzano-Agugliaro. Impact of the COVID-19 Pandemic on the Energy Use at the University of Almeria (Spain). Sustainability 2021, 13, 5843 .
AMA StyleMehdi Chihib, Esther Salmerón-Manzano, Mimoun Chourak, Alberto-Jesus Perea-Moreno, Francisco Manzano-Agugliaro. Impact of the COVID-19 Pandemic on the Energy Use at the University of Almeria (Spain). Sustainability. 2021; 13 (11):5843.
Chicago/Turabian StyleMehdi Chihib; Esther Salmerón-Manzano; Mimoun Chourak; Alberto-Jesus Perea-Moreno; Francisco Manzano-Agugliaro. 2021. "Impact of the COVID-19 Pandemic on the Energy Use at the University of Almeria (Spain)." Sustainability 13, no. 11: 5843.
The last seismic events showed that tunnel lining may suffer extensive damage. Employing numerical modeling has a great importance in predicting the seismic performance of tunnels. This paper tests the tunnel lining of the Zaouit Ait Mellal (ZAM) twin tunnels located between the cities of Marrakesh and Agadir in Morocco. Dynamic analysis was adopted by FLAC 2D software using the finite-difference elements. Four soil cross-sections were chosen, with different support devices installed along the twin tunnels, such as rock bolts and steel ribs. The seismic signals introduced as input were obtained from three different earthquakes: Al Hoceima 2004 in Morocco, EL Centro 1940 in the USA, and Kobe 1995 in Japan. The numerical results show that the deformation of the tunnel lining is more noteworthy in the sections using steel ribs compared to those using rock bolts, which is observed by the large values of relative displacement, reaching 1020 (mm) and 2.29 × 105 (N.m/m) of maximum bending moment. The analysis indicates that these sections present higher vulnerability during an earthquake, which should be considered when looking at the overall safety of the tunnel.
Abdelhay El Omari; Mimoun Chourak; El Echebba; Seif-Eddine Cherif; Carlos Navarro Ugena; Mohamed Rougui; Fadi Chehade; Francisco Lamas Fernández; Aboubakr Chaaraoui. Numerical Analysis of Twin Tunnels Lining under Different Seismic Conditions. Infrastructures 2021, 6, 29 .
AMA StyleAbdelhay El Omari, Mimoun Chourak, El Echebba, Seif-Eddine Cherif, Carlos Navarro Ugena, Mohamed Rougui, Fadi Chehade, Francisco Lamas Fernández, Aboubakr Chaaraoui. Numerical Analysis of Twin Tunnels Lining under Different Seismic Conditions. Infrastructures. 2021; 6 (2):29.
Chicago/Turabian StyleAbdelhay El Omari; Mimoun Chourak; El Echebba; Seif-Eddine Cherif; Carlos Navarro Ugena; Mohamed Rougui; Fadi Chehade; Francisco Lamas Fernández; Aboubakr Chaaraoui. 2021. "Numerical Analysis of Twin Tunnels Lining under Different Seismic Conditions." Infrastructures 6, no. 2: 29.
The type and the properties of the soil can potentially intensify the internal forces on buildings during seismic loads. To predict the effects of the soil parameters on the soil–structure interaction of buildings, it is necessary to consider the soil–structure interaction (SSI) in the modeling process. Therefore, this document aims to evaluate the seismic effect on the maximal displacement and inter-story drift, and evaluate the behavior of buildings under the second-order effect known in the literature as the P-delta effect. For this purpose, three cases of buildings with 5, 10 and 15 stories were modelled using a FLAC 2D finite-difference element calculation software with infinite soil conditions, including five types of base with four types of soil (one cohesive soil and three non-cohesive soils) considering the soil–structure interaction and a fixed base (without soil–structure interaction). According to the results for the above-mentioned boundary, as the height of the building increases and due to the weak properties of the soil, we notice that the maximal displacements and inter-story drift increase considerably. To that purpose, we recommend considering the second-order effect in seismic design, especially for non-cohesive soil.
El Echebba; Hasnae Boubel; Abdelday El Omari; Mohamed Rougui; Mimoun Chourak; Fadi Chehade. Analysis of the Second Order Effect of the SSI on the Building during a Seismic Load. Infrastructures 2021, 6, 20 .
AMA StyleEl Echebba, Hasnae Boubel, Abdelday El Omari, Mohamed Rougui, Mimoun Chourak, Fadi Chehade. Analysis of the Second Order Effect of the SSI on the Building during a Seismic Load. Infrastructures. 2021; 6 (2):20.
Chicago/Turabian StyleEl Echebba; Hasnae Boubel; Abdelday El Omari; Mohamed Rougui; Mimoun Chourak; Fadi Chehade. 2021. "Analysis of the Second Order Effect of the SSI on the Building during a Seismic Load." Infrastructures 6, no. 2: 20.
Remote sensing techniques based on medium resolution satellite imagery are being widely applied for mapping plastic covered greenhouses (PCG). This article aims at testing the spectral consistency of surface reflectance values of Sentinel-2 MSI (S2 L2A) and Landsat 8 OLI (L8 L2 and the pansharpened and atmospherically corrected product from L1T product; L8 PANSH) data in PCG areas located in Spain, Morocco, Italy and Turkey. The six corresponding bands of S2 and L8, together with the normalized difference vegetation index (NDVI), were generated through an OBIA approach for each PCG study site. The coefficient of determination (r2) and the root mean square error (RMSE) were computed in sixteen cloud-free simultaneously acquired image pairs from the four study sites to evaluate the coherence between the two sensors. It was found that the S2 and L8 correlation (r2 > 0.840, RMSE < 9.917%) was quite good in most bands and NDVI. However, the correlation of the two sensors fluctuated between study sites, showing occasional sun glint effects on PCG roofs related to the sensor orbit and sun position. Moreover, higher surface reflectance discrepancies between L8 L2 and L8 PANSH data, mainly in the visible bands, were always observed in areas with high-level aerosol values derived from the aerosol quality band included in the L8 L2 product (SR aerosol). In this way, the consistency between L8 PANSH and S2 L2A was improved mainly in high-level aerosol areas according to the SR aerosol band.
Manuel Aguilar; Rafael Jiménez-Lao; Abderrahim Nemmaoui; Fernando Aguilar; Dilek Koc-San; Eufemia Tarantino; Mimoun Chourak. Evaluation of the Consistency of Simultaneously Acquired Sentinel-2 and Landsat 8 Imagery on Plastic Covered Greenhouses. Remote Sensing 2020, 12, 2015 .
AMA StyleManuel Aguilar, Rafael Jiménez-Lao, Abderrahim Nemmaoui, Fernando Aguilar, Dilek Koc-San, Eufemia Tarantino, Mimoun Chourak. Evaluation of the Consistency of Simultaneously Acquired Sentinel-2 and Landsat 8 Imagery on Plastic Covered Greenhouses. Remote Sensing. 2020; 12 (12):2015.
Chicago/Turabian StyleManuel Aguilar; Rafael Jiménez-Lao; Abderrahim Nemmaoui; Fernando Aguilar; Dilek Koc-San; Eufemia Tarantino; Mimoun Chourak. 2020. "Evaluation of the Consistency of Simultaneously Acquired Sentinel-2 and Landsat 8 Imagery on Plastic Covered Greenhouses." Remote Sensing 12, no. 12: 2015.
The main purpose of this study is to assess seismic risk and present earthquake loss scenarios for the city of Imzouren, in northern Morocco. An empirical approach was chosen to assess the seismic vulnerability of the existing buildings, using the Vulnerability Index Method (RISK-UE), and considering two earthquake scenarios (deterministic and probabilistic). Special concern was given to the seismic vulnerability in Imzouren since the 2004 earthquake (24 February, mw = 6.4) that struck the region and caused substantial damage. A site investigation was conducted in the city targeting more than 3000 residential buildings, which had been closely examined and catalogued to assess their seismic vulnerability. The results of the seismic risk assessment in the city are represented through damage to the buildings, harm to the population and economic loss. Generally, the results obtained from the deterministic approach are in agreement with the damage caused by the 2004 earthquake.
Seif-Eddine Cherif; Mimoun Chourak; Mohamed Abed; Abdelhalim Douiri. Potential Seismic Damage Assessment of Residential Buildings in Imzouren City (Northern Morocco). Buildings 2018, 8, 179 .
AMA StyleSeif-Eddine Cherif, Mimoun Chourak, Mohamed Abed, Abdelhalim Douiri. Potential Seismic Damage Assessment of Residential Buildings in Imzouren City (Northern Morocco). Buildings. 2018; 8 (12):179.
Chicago/Turabian StyleSeif-Eddine Cherif; Mimoun Chourak; Mohamed Abed; Abdelhalim Douiri. 2018. "Potential Seismic Damage Assessment of Residential Buildings in Imzouren City (Northern Morocco)." Buildings 8, no. 12: 179.
Al Hoceima is one of the most seismic active regions in north of Morocco. It is demonstrated by the large seismic episodes reported in seismic catalogs and research studies. However, seismic risk is relatively high due to vulnerable buildings that are either old or don’t respect seismic standards. Our aim is to present a study about seismic risk and seismic scenarios for the city of Al Hoceima. The seismic vulnerability of the existing residential buildings was evaluated using the vulnerability index method (Risk-UE). It was chosen to be adapted and applied to the Moroccan constructions for its practicality and simple methodology. A visual inspection of 1102 buildings was carried out to assess the vulnerability factors. As for seismic hazard, it was evaluated in terms of macroseismic intensity for two scenarios (a deterministic and probabilistic scenario). The maps of seismic risk are represented by direct damage on buildings, damage to population and economic cost. According to the results, the main vulnerability index of the city is equal to 0.49 and the seismic risk is estimated as Slight (main damage grade equal to 0.9 for the deterministic scenario and 0.7 for the probabilistic scenario). However, Moderate to heavy damage is expected in areas located in the newer extensions, in both the east and west of the city. Important economic losses and damage to the population are expected in these areas as well. The maps elaborated can be a potential guide to the decision making in the field of seismic risk prevention and mitigation strategies in Al Hoceima.
Seif-Eddine Cherif; Mimoun Chourak; Mohamed Abed; Luis Pujades. Seismic risk in the city of Al Hoceima (north of Morocco) using the vulnerability index method, applied in Risk-UE project. Natural Hazards 2016, 85, 329 -347.
AMA StyleSeif-Eddine Cherif, Mimoun Chourak, Mohamed Abed, Luis Pujades. Seismic risk in the city of Al Hoceima (north of Morocco) using the vulnerability index method, applied in Risk-UE project. Natural Hazards. 2016; 85 (1):329-347.
Chicago/Turabian StyleSeif-Eddine Cherif; Mimoun Chourak; Mohamed Abed; Luis Pujades. 2016. "Seismic risk in the city of Al Hoceima (north of Morocco) using the vulnerability index method, applied in Risk-UE project." Natural Hazards 85, no. 1: 329-347.
A quantitative assessment of forest cover change in the Moulouya River watershed (Morocco) was carried out by means of an innovative approach from atmospherically corrected reflectance Landsat images corresponding to 1984 (Landsat 5 Thematic Mapper) and 2013 (Landsat 8 Operational Land Imager). An object-based image analysis (OBIA) was undertaken to classify segmented objects as forested or non-forested within the 2013 Landsat orthomosaic. A Random Forest classifier was applied to a set of training data based on a features vector composed of different types of object features such as vegetation indices, mean spectral values and pixel-based fractional cover derived from probabilistic spectral mixture analysis). The very high spatial resolution image data of Google Earth 2013 were employed to train/validate the Random Forest classifier, ranking the NDVI vegetation index and the corresponding pixel-based percentages of photosynthetic vegetation and bare soil as the most statistically significant object features to extract forested and non-forested areas. Regarding classification accuracy, an overall accuracy of 92.34% was achieved. The previously developed classification scheme was applied to the 1984 Landsat data to extract the forest cover change between 1984 and 2013, showing a slight net increase of 5.3% (ca. 8800 ha) in forested areas for the whole region.
Fernando J. Aguilar; Abderrahim Nemmaoui; Manuel A. Aguilar; Mimoun Chourak; Yassine Zarhloule; Andrés M. García Lorca. A Quantitative Assessment of Forest Cover Change in the Moulouya River Watershed (Morocco) by the Integration of a Subpixel-Based and Object-Based Analysis of Landsat Data. Forests 2016, 7, 23 .
AMA StyleFernando J. Aguilar, Abderrahim Nemmaoui, Manuel A. Aguilar, Mimoun Chourak, Yassine Zarhloule, Andrés M. García Lorca. A Quantitative Assessment of Forest Cover Change in the Moulouya River Watershed (Morocco) by the Integration of a Subpixel-Based and Object-Based Analysis of Landsat Data. Forests. 2016; 7 (12):23.
Chicago/Turabian StyleFernando J. Aguilar; Abderrahim Nemmaoui; Manuel A. Aguilar; Mimoun Chourak; Yassine Zarhloule; Andrés M. García Lorca. 2016. "A Quantitative Assessment of Forest Cover Change in the Moulouya River Watershed (Morocco) by the Integration of a Subpixel-Based and Object-Based Analysis of Landsat Data." Forests 7, no. 12: 23.
The southern Gibraltar Arc’s bloc (Rif’s belt) has a complex geological setting including peridotites outcropping in the Rif and Betic. They are among the largest infracontinental mantle rock outcrops worldwide. In spite of several geological studies, the deep structure of this area remains poorly defined. The aim of this work is giving a reliable geometry of the major geological structures of the Rif, especially the peridotite bodies and faults or geological contacts. The results obtained from a multiscale analysis of geological contacts applied to gravity and aeromagnetic data were used to generate a structural map of the studied area. This method in association with the Euler method allowed estimating the strike direction, shape, dip, and depth of contacts. The map gives a model of the region and confirms the existence of several faults, localized or inferred, from former geological studies. This study suggests a large extension of the Beni Bousera peridotites on the offshore from Jebha to Ceuta, and highlights an extended anomaly related to deeper crops probably ophiolite remnant of the suture zone.
Najib Amar; Driss Khattach; Ali Azdimousa; Mimoun Chourak; Antonio Jabaloy; Ahmed Manar; Mounir Amar. Structure and peridotite of Gibraltar arc southern bloc: gravimetric and aeromagnetic evidences. Arabian Journal of Geosciences 2015, 8, 9801 -9813.
AMA StyleNajib Amar, Driss Khattach, Ali Azdimousa, Mimoun Chourak, Antonio Jabaloy, Ahmed Manar, Mounir Amar. Structure and peridotite of Gibraltar arc southern bloc: gravimetric and aeromagnetic evidences. Arabian Journal of Geosciences. 2015; 8 (11):9801-9813.
Chicago/Turabian StyleNajib Amar; Driss Khattach; Ali Azdimousa; Mimoun Chourak; Antonio Jabaloy; Ahmed Manar; Mounir Amar. 2015. "Structure and peridotite of Gibraltar arc southern bloc: gravimetric and aeromagnetic evidences." Arabian Journal of Geosciences 8, no. 11: 9801-9813.
We have determined the three-dimensional P-wave velocity structure of the crust and uppermost mantle beneath the Iberia-Africa collision zone using local earthquake tomography. We have inverted arrival times of first-arriving P phases listed in the bulletins of the Instituto Geográfico Nacional and phases picked by us on permanent stations of other regional networks and on temporary broadband stations deployed in the frame of the TOPO-IBERIA project. In total we have used 38,624 P-wave arrival times from 2362 local events recorded at 120 seismic stations. The most remarkable result is the imaging of a large high velocity body following approximately the western Alboran coastline, with a horizontal dimension of at least 200. km and extending in depth from the surface down to 24. km. This body, not imaged previously with this extent using seismic tomography, coincides with surface exposures of subcontinental mantle (peridotites) in Iberia and Africa and with a belt of positive gravity anomalies. We have also found a marked contrast in the seismic velocities of the middle and lower crust of the Alboran basin, coinciding with the location of the Trans-Alboran Shear Zone. We attribute this contrast to widespread magmatic intrusions in the eastern part of the basin, resulting in higher P-wave velocities than in the west. This contrast would also explain the different orientation of the Trans-Alboran Shear zone with respect to the surface features and faults in the Alboran basin. We also image thick crust beneath the Betics and Rif, accompanied by downgoing lithosphere of the Iberian foreland and Gulf of Cadiz beneath the Betic-Rif-Alboran system.This is a contribution of the Team Consolider-Ingenio 2010 TOPO-IBERIA (CSD2006-00041).Additional funding was provided by the SIBERIA (CGL2006-01171), RIFSIS\ud (CGL2009-09727) and ALERTES-RIM (CGL2013-45724-C3-3-R) projectsPeer Reviewe
Lahcen El Moudnib; Antonio Villasenor; Mimoun Harnafi; Josep Gallart; Antonio Pazos; Inmaculada Serrano; Diego Córdoba; Javier A. Pulgar; Pedro Ibarra; Mohammed M. Himmi; Mimoun Chourak. Crustal structure of the Betic–Rif system, western Mediterranean, from local earthquake tomography. Tectonophysics 2015, 643, 94 -105.
AMA StyleLahcen El Moudnib, Antonio Villasenor, Mimoun Harnafi, Josep Gallart, Antonio Pazos, Inmaculada Serrano, Diego Córdoba, Javier A. Pulgar, Pedro Ibarra, Mohammed M. Himmi, Mimoun Chourak. Crustal structure of the Betic–Rif system, western Mediterranean, from local earthquake tomography. Tectonophysics. 2015; 643 ():94-105.
Chicago/Turabian StyleLahcen El Moudnib; Antonio Villasenor; Mimoun Harnafi; Josep Gallart; Antonio Pazos; Inmaculada Serrano; Diego Córdoba; Javier A. Pulgar; Pedro Ibarra; Mohammed M. Himmi; Mimoun Chourak. 2015. "Crustal structure of the Betic–Rif system, western Mediterranean, from local earthquake tomography." Tectonophysics 643, no. : 94-105.
Based on passive seismic interferometry applied to ambient seismic noise recordings between station pairs belonging to a small-scale array, we have obtained shear wave velocity images of the uppermost materials that make up the Dead Sea Basin. We extracted empirical Green’s functions from cross-correlations of long-term recordings of continuous data, and measured inter-station Rayleigh wave group velocities from the daily correlation functions for positive and negative correlation time lags in the 0.1–0.5 Hz bandwidth. A tomographic inversion of the travel times estimated for each frequency is performed, allowing the laterally varying 3-D surface wave velocity structure below the array to be retrieved. Subsequently, the velocity-frequency curves are inverted to obtain S-wave velocity images of the study area as horizontal depth sections and longitude- and latitude-depth sections. The results, which are consistent with other previous ones, provide clear images of the local seismic velocity structure of the basin. Low shear velocities are dominant at shallow depths above 3.5 km, but even so a spit of land with a depth that does not exceed 4 km is identified as a salt diapir separating the low velocities associated with sedimentary infill on both sides of the Lisan Peninsula. The lack of low speeds at the sampling depth of 11.5 km implies that there are no sediments and therefore that the basement is near 10–11 km depth, but gradually decreasing from south to north. The results also highlight the bowl-shaped basin with poorly consolidated sedimentary materials accumulated in the central part of the basin. The structure of the western margin of the basin evidences a certain asymmetry both whether it is compared to the eastern margin and it is observed in north–south direction. Infill materials down to ∼8 km depth are observed in the hollow of the basin, unlike what happens in the north and south where they are spread beyond the western Dead Sea shore.
José Badal; Yun Chen; Mimoun Chourak; Jacek Stankiewicz. S-wave velocity images of the Dead Sea Basin provided by ambient seismic noise. Journal of Asian Earth Sciences 2013, 75, 26 -35.
AMA StyleJosé Badal, Yun Chen, Mimoun Chourak, Jacek Stankiewicz. S-wave velocity images of the Dead Sea Basin provided by ambient seismic noise. Journal of Asian Earth Sciences. 2013; 75 ():26-35.
Chicago/Turabian StyleJosé Badal; Yun Chen; Mimoun Chourak; Jacek Stankiewicz. 2013. "S-wave velocity images of the Dead Sea Basin provided by ambient seismic noise." Journal of Asian Earth Sciences 75, no. : 26-35.
In this paper, we perform a comprehensive explanation of the geophysical inversion of gravity data, as well as, how it can be used to determine the Moho undulation and the crustal structure. This inversion problem and the necessary assumptions to solve it will be described in this paper joint to the methodology used to invert gravity data (gravity anomalies). In addition, the application of this method to the determination of the Moho undulation will be performed computing the Moho undulation in the Moroccan area, as an example. Before the inversion, it is necessary the removing of the gravity effects for shallow and very deep structures, to obtain the deep gravity anomaly field that is associated to the deep structure and Moho undulation. These effects will be removed by a filtering process of the gravity anomaly field and by subtraction of the gravity anomalies corresponding to the very deep structure. The results presented in this paper will show that the inversion of gravity data is a powerful tool, to research the structure of the crust and the upper mantle. By means of this inversion process, the principal structural features beneath of Morocco area will be revealed
Victor Corchete; Mimoun Chourak; Driss Khattach. A Methodology for Filtering and Inversion of Gravity Data: An Example of Application to the Determination of the Moho Undulation in Morocco. Engineering 2010, 02, 149 -159.
AMA StyleVictor Corchete, Mimoun Chourak, Driss Khattach. A Methodology for Filtering and Inversion of Gravity Data: An Example of Application to the Determination of the Moho Undulation in Morocco. Engineering. 2010; 02 (03):149-159.
Chicago/Turabian StyleVictor Corchete; Mimoun Chourak; Driss Khattach. 2010. "A Methodology for Filtering and Inversion of Gravity Data: An Example of Application to the Determination of the Moho Undulation in Morocco." Engineering 02, no. 03: 149-159.
The orthometric heights can be obtained without levelling by means of the ellipsoidal and geoidal heights. For engineering purposes, these orthometric heights must be determined with high accuracy. For this reason, the determination of a high-resolution geoid is necessary. In Andalusia (South Spain) a new geopotential model (EIGEN-GL04C) has been available since the publication of a more recent regional geoid. As a consequence, these new data bring about improvements that ought to be included in a new regional geoid of Andalusia. With this aim in mind, a new gravimetric geoid determination has been carried out, in which these new data have been included. Thus, a new geoid is provided as a data grid distributed for the South Spain area from 36 to 39 degrees of latitude and –7 to –1 degrees of longitude (extending to 3 × 6 degrees), in a 120 × 240 regular grid with a mesh size of 1.5’ × 1.5’ and 28800 points in the GRS80 reference system. This calculated geoid and previous geoids are compared to the geoid undulations obtained for 262 GPS/levelling points, distributed within the study area. The new geoid shows an improvement in accuracy and reliability, fitting the geoidal heights determined for these GPS-levelling points better than any previous geoid
Francisco Manzano; Victor Corchete; Mimoun Chourak; Gil Manzano. Determination of a Gravimetric Geoid Solution for Andalusia (South Spain). Engineering 2010, 02, 160 -165.
AMA StyleFrancisco Manzano, Victor Corchete, Mimoun Chourak, Gil Manzano. Determination of a Gravimetric Geoid Solution for Andalusia (South Spain). Engineering. 2010; 02 (03):160-165.
Chicago/Turabian StyleFrancisco Manzano; Victor Corchete; Mimoun Chourak; Gil Manzano. 2010. "Determination of a Gravimetric Geoid Solution for Andalusia (South Spain)." Engineering 02, no. 03: 160-165.
V. Corchete; Mimoun Chourak; D. Khattach; E.H. Benaïm. The high-resolution gravimetric geoid of Morocco: MORGEO. Journal of African Earth Sciences 2007, 48, 267 -272.
AMA StyleV. Corchete, Mimoun Chourak, D. Khattach, E.H. Benaïm. The high-resolution gravimetric geoid of Morocco: MORGEO. Journal of African Earth Sciences. 2007; 48 (4):267-272.
Chicago/Turabian StyleV. Corchete; Mimoun Chourak; D. Khattach; E.H. Benaïm. 2007. "The high-resolution gravimetric geoid of Morocco: MORGEO." Journal of African Earth Sciences 48, no. 4: 267-272.
Mimoun Chourak. Imaging of the Near-Surface Shear-Wave Velocity Structure of the Granada Basin (Southern Spain). Bulletin of the Seismological Society of America 2003, 93, 430 -442.
AMA StyleMimoun Chourak. Imaging of the Near-Surface Shear-Wave Velocity Structure of the Granada Basin (Southern Spain). Bulletin of the Seismological Society of America. 2003; 93 (1):430-442.
Chicago/Turabian StyleMimoun Chourak. 2003. "Imaging of the Near-Surface Shear-Wave Velocity Structure of the Granada Basin (Southern Spain)." Bulletin of the Seismological Society of America 93, no. 1: 430-442.
A dispersion analysis of Rg waves generated by local earthquakes surrounding the Alboran Sea (Western Mediterranean) has been undertaken to obtain its shear-wave velocity structure at shallow depths. We have used single-component short-period stations belonging to the Regional Seismic Network of Andalucia and the Spanish National Seismic Network. Our database includes seismograms generated by 18 earthquakes that occurred in the area during the period of 1992–95. The seismic events, with magnitudes between 2.9 and 4.9 and focal depths ranging from 2.7 to 12 km, were recorded at 13 stations at distances between 91 and 245 km from the source. We have analysed a total of 20 source-station Rg-wave paths. These seismic trajectories across the Alboran Sea provide irregular path coverage due to their geographical location. Despite sparse sampling the data collected have been processed with the help of digital filtering and group velocity dispersion curves have been obtained. The path group velocities vary from 1.21 to 1.91 km s −1 within the 1.7–5.8 s period interval. Then using a generalised inversion approach we have obtained 1D shear-wave velocity models for all source-station paths. Inversion for shear velocity structure gives velocity profiles down to a depth of 5 km. The shear-wave velocities range between 0.7 and 3.2 km s −1 within the standard deviation band of 0.05–0.17 km s −1 , and show significant variations from each other in the region of the Alboran Basin. We have applied an imaging technique aimed at volumetric modelling and data visualisation and we hereby present the tomographic results based on ray-path seismic velocities that were obtained for the basin. We have got an overall view of the sedimentary cover of the area regarding its geometry and S-wave velocity structure at very shallow depths (0–5 km). Although the relationship between lateral change in Rg dispersion and geologic structure may not be straightforward, we have observed a good correlation between those changes and surface geology. Keywords Rg waves dispersion inversion tomography Alboran Sea 1 Brief introduction 1.1 About the study area The Alboran Sea, in the westernmost Mediterranean, is a small region between the Iberian Peninsula and northern Africa roughly outlined by 5.3 and 2.0 degrees of west longitude and 35.2 and 36.7 degrees of north latitude. It is a narrow basin about 160 km wide and 360 km long bordered by peripheral orogenic belts like the Betic (southern Spain) and Rif (Morocco) mountain belts, to the north and south, respectively, and the Algerian Basin and the South Balearic Basin to east ( Fig. 1 ) . The Alboran Sea, with a complex bathymetry and a water depth of less than 2000 m, is underlain by thinned continental crust. A transition to oceanic crust occurs beneath the Algerian basin. The Moho varies between 25 km onshore and about 14 km beneath the central zone. The sediments of the basin are of marine origin and form a thick layer overlying the continental crust beneath Alboran. The basement is composed of Palaeozoic sediments metamorphosed during the Alpine orogeny ( Soto and Platt, 1995 ). Fig. 1 shows the Alboran Basin divided into two major zones, the Western Alboran Basin (WAB) where some diapiric formations arise, and the Eastern Alboran Basin (EAB) where deformation, essentially due to fracturing, is pronounced. Geomagnetic data in the Alboran Basin indicate many volcanic intrusions, especially in the eastern part. Actually, the ridge dividing the basin is partly of volcanic origin and the Alboran Island, just located on the central ridge ( Fig. 1 ), is composed of volcanic rocks. To a great extent the Alboran Basin is surrounded by the Alboran domain and by flysch trough units to the west and southwest, and already in Africa, to the south and southeast, by the Maghrebian domain and Neogene basins on land. It shows specific geologic and geophysical features that have attracted the attention of many researchers. In fact, the Alboran Sea has been identified, together with the Calabrian and Hellenic arc regions, as one of the Mediterranean areas with the greatest potential for addressing questions related to deformation processes at convergent plate boundary systems. Moreover, the importance of the region is widely considered in geodynamics for plate tectonic reconstructions, as it straddles the boundary between the African and Eurasian plates. The geologic structure and the principal neotectonic and geophysical characteristics of the region are aspects well investigated using different methods and techniques by several authors (Here we supply some references where information of interest can be found). A summary of the geodynamic setting of the Alboran Sea can be found in Maldonado and Comas (1992) . Jurado and Comas (1992) describe the lithological units and the geometry of the sedimentary bodies since the Lower Miocene found in the northern part of the Alboran Sea. Woodside and Maldonado (1992) , after a preliminary interpretation of high-resolution seismic reflection profiles, have given a general description of the structural and tectonic features of the area (mayor fault systems, basins, ridges, banks) and reported styles of compressional neotectonics and the principal neotectonic elements in the eastern Alboran Sea. Concerning the mechanisms for thinning of the crust and subsidence of the Alboran Sea, several interpretations have been proposed up to now, which clearly reflect the conflicting opinions about these phenomena. Extensional detachment systems superimposed on the Betic and Rifean belts after continental collision are postulated to have produced crustal thinning and tectonic subsidence ( Galindo-Zaldı́var et al., 1989 ), though tectonic subsidence is relatively minor in the Alboran Sea compared to the Western Mediterranean ( Pasqual et al., 1996 ) in general. Superimposed on tectonic extension, plate...
Mimoun Chourak; J. Badal; V. Corchete; F.J. Seron. A survey of the shallow structure beneath the Alboran Sea using Rg-waves and 3D imaging. Tectonophysics 2001, 335, 255 -273.
AMA StyleMimoun Chourak, J. Badal, V. Corchete, F.J. Seron. A survey of the shallow structure beneath the Alboran Sea using Rg-waves and 3D imaging. Tectonophysics. 2001; 335 (3):255-273.
Chicago/Turabian StyleMimoun Chourak; J. Badal; V. Corchete; F.J. Seron. 2001. "A survey of the shallow structure beneath the Alboran Sea using Rg-waves and 3D imaging." Tectonophysics 335, no. 3: 255-273.