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  • 1
    Electronic Resource
    Electronic Resource
    Crustal structure along a traverse across the Middle and High Atlas mountains derived from seismic refraction studies (1992)
    Springer
    International journal of earth sciences 81 (1992), S. 237-248 
    Details
    ISSN: 1437-3262
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Abstract In 1986 explosion seismic investigations have been carried out along a traverse of about 350 km length running from NNW to SSE crossing the High and Middle Atlas. Two further profiles run E/W through the Middle and NW-SE through the High Atlas. Neither the High nor the Middle Atlas mountains have a significant root. The maximum thickness of crust with 38–39 km is found under the northern border of the High Atlas. South and north of the High Atlas the crustal thickness amounts to 35 km. The upper as well as the lower crust are stongly structurized in the vertical direction. Significant for the profiles observed is the change between high and low velocities in the whole crust. The velocities at the uppermost mantle are relatively low with values of 7.7–7.9 km/s. The average velocities for the whole crust are 6.1–6.2 km/s.
    Abstract: Résumé Durant l'année 1986 des sondages sismiques de tirs ont été entrepris le long d'une traverse d'environ 350 km de longueur se dirigeant du nord nordouest au sud sud-est et parcourant le Haut et Moyen Atlas. Deux autres profils parcourent le Moyen Atlas de l'est à l'ouest et le Haut Atlas du nord-ouest au sud-est. Le Haut et Moyen Atlas ne possèdent pas de racine montagneuse. L'épaisseur maximale de 38–39 km de la croûte a été localisée sous le bord nord du Haut Atlas. Au sud et au nord du Haut Atlas l'épaisseur de la croûte s'élève à 35 km. La croûte supérieure ainsi que la croûte inférieure est très structurée en direction verticale. Ce qui est caractéristique pour tous les profils observés c'est un changement rapide entre de grandes et petites vitesses et concernant le total de la croûte. Les vitesses dans le manteau le plus élevé haut sont relativement basses avec 7,7–7,9 km/s. Les vitesses moyennes pour la croûte entière sont de 6,1 à 6,2 km/s.
    Notes: Zusammenfassung Sprengseismische Untersuchungen wurden 1986 längs einer etwa 350 km langen Traverse durchgeführt, die NNW-SSO verläuft und den Mittleren und den Hohen Atlas quert. Zwei weitere Profile verlaufen E-W durch den Mittleren und NW-SO durch den Hohen Atlas. Der Hohe und der Mittlere Atlas besitzen keine ausgeprägte Gebirgswurzel. Die maximale Krustendicke wird mit 38–39 km unter dem nördlichen Rand des Hohen Atlas angetroffen. Südlich und nördlich vom Hohen Atlas beträgt die Krustenmächtigkeit 35 km. Sowohl die obere als auch die untere Kruste sind in vertikaler Richtung stark strukturiert. Auf allen beobachteten Profilen ist ein Wechsel zwischen hohen und niedrigen Geschwindigkeiten für die gesamte Kruste charakteristisch. Die Geschwindigkeiten im obersten Mantel sind mit Werten von 7.7–7.9 km/s relativ niedrig. Die Durchschnittsgeschwindigkeiten für die gesamte Kruste liegen bei 6.1–6.2 km/s.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01764552
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    Paper (German National Licenses)
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  • 2
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    Geodynamic implications of intermediate-depth earthquakes and volcanism in the intraplate Atlas mountains (Morocco) (1998)
    Elsevier
    Details
    Publication Date: 1998-07-01
    Print ISSN: 0031-9201
    Electronic ISSN: 1872-7395
    Topics: Geosciences , Physics
    Published by Elsevier
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  • 3
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    Evidence for subduction beneath Gibraltar Arc and Andean regions from k-means earthquake centroids (2014)
    Springer
    Details
    Publication Date: 2014-09-03
    Description: k-Means algorithms are widely used for determining clusters in broad types of datasets. Since zones of high seismic activity as plate boundary present diffuse seismicity patterns, the use of k-algorithm is a way to classify earthquakes in terms of centroids. Mapping centroids improves seismic visibility for further tectonic interpretation. We used selected datasets of earthquakes and determined the number of clusters or values of k by introducing the silhouette index method to check the validity of cluster numbers. By introducing magnitude size in the vectorial attributes, k-means algorithm provides a map of centroids that represents the location of high seismic energy, which is useful in seismic risk assessment. By including the depth of seismic events as the main attribute, we obtained spatiotemporal variations of centroids, which improve the image resolution of seismicity at depth to find out the underlying dynamic process. This has been achieved in subduction zone of Chile where the presence of slab is reflected by centroid distribution. The method is particularly relevant to complex seismic zones where controversial geodynamic models are reported such as the Gibraltar Arc. Resulting model supports W-oriented subduction underlying many parts of the Gibraltar zone. © 2014, Springer Science+Business Media Dordrecht.
    Print ISSN: 1383-4649
    Electronic ISSN: 1573-157X
    Topics: Geosciences , Physics
    Published by Springer
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  • 4
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    Crustal structure along a traverse across the Middle and High Atlas mountains derived from seismic refraction studies (1992)
    Springer
    Details
    Publication Date: 1992-02-01
    Print ISSN: 0016-7835
    Electronic ISSN: 1432-1149
    Topics: Geosciences
    Published by Springer
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  • 5
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    Preliminary results from the first geomagnetic deep sounding in the Western sector of the Anti Atlas region, Southern Morocco (2010)
    Details
    Publication Date: 2017-04-04
    Description: An array of vector magnetometers was temporarily installed in the Western sector of the Anti Atlas chain, Morocco in the frame of the Geomagnetic Depth Sounding (GDS) technique. As a fruitful collaboration between Italy and Morocco, the joint project “Terremagnet”, funded by the Italian Ministry of the Foreign Affair, was aimed to local observations of the Earth’s magnetic field in order to define electric conductivity horizontal and vertical contrasts in a tectonic active region. The analysis in time and frequency-domain for tests on the induced EM field dimension, computations of single site and coupled site Transfer Functions (TFs) and induction vectors configuration are shown. Recorded data are compared to Averroes geomagnetic observatory (Morocco) (IAGA code: AVE, lat. 33° 17’ 53” N, long. 7° 24’ 48” W, altitude: 230 m a.s.l.). The preliminary results from Morocco are really encouraging and pointed out good data samplings that will allow shedding up light on the tectonic setting of this peculiar region of the Anti-Atlas.
    Description: Published
    Description: Hosted by the U.S. Geological Survey’s (USGS) Geomagnetism Program, the workshop’s measurement session was held at the Boulder Observatory and the scientific session was held on the campus of the Colorado School of Mines in Golden, Colorado
    Description: 1.6. Osservazioni di geomagnetismo
    Description: 2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive
    Description: 3.4. Geomagnetismo
    Description: open
    Keywords: Absolute measurements ; Magnetic Anomalies ; GDS ; Morocco ; 04. Solid Earth::04.05. Geomagnetism::04.05.08. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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