New evidence of delamination in the Western Alboran Sea

Timoulali, Youssef; Djellit, Hamou; Hahou, Youssef; Jabour, Nacer; Merrouch, Redouane

doi:10.1016/j.jog.2013.10.005

Cited by 9 publications

(4 citation statements)

References 44 publications

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“…Finally, at depth, tomographic maps obtained by [54] show a low-velocity zone at 15 km depth near Al Ho-ceima; however, the resolution of the maps is not appropriate for determining accurate orientations. Instead, the higher resolution tomography obtained by [36] clearly shows that the aftershock hypocentres are located within high velocity zones at 5 -15 km depth, whose orientation is in conformity with the chosen faults, which may not be an artifact of the used methodology.…”

Section: Seismogenic Faults In the Al Hoceima Areamentioning

confidence: 97%

“…Authors [53] inferred low velocity zones within the layer 5 km beneath the Nekor graben and within the lower crust in the continental area, whereas the most important high velocity zone is located south of Al Hoceima city within the layer 10 km. Tomographic maps of [54] show a low-velocity zone at 15 km depth near Al Hoceima; however, the resolution is not appropriate for determining better orientations. Instead, the higher resolution tomography obtained by [36] shows better constrained velocity zones at 5 -15 km depth, with a determinable orientation.…”

Section: Deep Structurementioning

confidence: 97%

“…[49] [50] show that the thickness of the crust in northern Morocco decreases northwards from 30 km in the Rif to 12 km in the central Alboran basin, whereas the depth of the lithosphere-asthenosphere boundary in the area decreases from 230 -250 km in the west, to about 70 km in the Alboran Sea, the isobaths running roughly N-S. Crustal thinning is accompanied by the development of a large thermal anomaly in the Alboran basin [51]. Around Al Hoceima, the deep structure was mainly studied using seismic tomography [36] [52]- [54]. The results obtained by these authors appear strongly related to the network configuration, and especially to the distance between recording stations; for instance, P-wave velocity maps obtained by [52] show in the layer 5 -15 km a large circular (~100 km diameter), high velocity zone south-east of Al Hoceima, which extends at depth in the layer 15 -30 km, contiguous to a high velocity zone.…”

Section: Deep Structurementioning

confidence: 99%

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Coulomb Stress Perturbations Related to the Al Hoceima (Morocco) Earthquakes of 1994 and 2004

Medina¹

2015

OJER

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This paper exposes the results of the study of the stress perturbations caused by the Al Hoceima (Morocco) earthquakes of 1994 and 2004 by means of Coulomb modeling. Modeling was based on the compilation of all the studies carried out after both events, including seismological (location and depth of the main shocks and aftershocks), seismotectonic (source parameters, stress field), geodetic (GPS), tomographic and geological ones. It shows that the first earthquake is likely to have induced the second one when adopting appropriate epicenter locations, source and receiver fault planes. In detail, the model shows that motion along the N23E oriented Bousekkour-Aghbal fault in 1994 activated the eastern segment of a previously unknown NW-SE fault located at its southern end, which in turn originated the 2004 earthquake. The model also provides a suitable explanation for the distribution of the aftershock clusters. Finally, an attempt of prediction of the next event shows that it is likely to occur on NE-SW planes located to the NW (Bokkoya and offshore) and SE (reaching the Nekor fault) of the NW-SE fault, while Al Hoceima city should remain in a shadow zone.

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Section: Seismogenic Faults In the Al Hoceima Areamentioning

confidence: 97%

Section: Deep Structurementioning

confidence: 97%

Section: Deep Structurementioning

confidence: 99%

See 1 more Smart Citation

Coulomb Stress Perturbations Related to the Al Hoceima (Morocco) Earthquakes of 1994 and 2004

Medina¹

2015

OJER

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“…Such studies have been conducted to investigate the local crustal structure and better understand the geological and tectonic processes that have shaped the region [Gil et al, 2014;Mancilla and Diaz, 2015;Timoulali et al, 2014aTimoulali et al, , 2022. These studies use various geophysical techniques, such as seismic reflection and refraction, seismic/electrical tomography, magnetic surveys, and stations measurements to map the subsurface structure as well as the basins geometry [for Deep Seismic Sounding in the Alboran Sea 1974Sea , 1978Gurrria and Mezcua, 2000;Timoulali et al, 2014;El Fellah et al, 2019;EL Hilali et al, 2021;Taj et al, 2024].…”

Section: Introductionmentioning

confidence: 99%

Crustal Attenuation Tomographic Image of Northern Morocco: Indication of High Tectonic Activities

Najim,

El Hilali,

Timoulali

et al. 2024

Annals of Geophysics

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Northern Morocco is known by its complex tectonic activity and has been the subject of various geophysical and geodynamic studies aimed to understand the physical properties and composition of the Earth’s crust and upper mantle. The waveforms of earthquakes recorded by the Topo – Iberia – Picasso seismic networks from 2008 to 2012 are analyzed to determine the decay properties of the coda wave and map the attenuation and absorption properties of the crust in this region. The coda quality factor Qc was estimated in five non‑overlapping frequency windows, ranging from 1.5 to 24 Hz, using recordings of local earthquakes. The measurements of Qc were then used to create maps of the absorption quality factor (Qi) using a linearized approximation. These maps were compared with the tectonic settings of the region to gain further insight into the crustal properties. Lateral and vertical variations of the coda quality factor (Qc) were investigated by creating a three‑dimensional tomographic image of the region. The results showed strong lateral variations of absorption in the northern part of Morocco, indicating high tectonic activity. Areas with high tectonic activity and high absorption were characterized by low values of Qc, while areas with low tectonic activity and low absorption had high values of Qc. The areas with thick cover sedimentary materials and shallow geothermal activity showed low‑frequency absorption. When compared to previous studies in northern Morocco, the study provides new information about the three‑dimensional attenuation model of the Earth’s crust.

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Lithosphere delamination in continental collisional orogens: A systematic numerical study

2016

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Lithosphere delamination is believed to have played a major role in mountain building; however, the mechanism and dynamics of delamination remain poorly understood. Using a 2‐D high‐resolution thermomechanical model, we systematically investigated the conditions for the initiation of lithosphere delamination during orogenesis of continental collision and explored the key factors that control the various modes of delamination. Our results indicate that the negative buoyancy from lithosphere thickening during orogenesis could cause delamination, when the reference density of the lithospheric mantle is not lower than that of the asthenosphere. In these cases, compositional rejuvenation of depleted continental lithosphere by magmatic/metasomatic plume‐ and/or subduction‐induced processes may play crucial roles for subsequent lithosphere delamination. If the reference density of the lithospheric mantle is less than that of the asthenosphere, additional promoting factors, such as lower crust eclogitization, are required for delamination. Our numerical simulations predict three basic modes of lithosphere delamination: pro‐plate delamination, retro‐plate delamination, and a transitional double‐plates (both the pro‐plate and retro‐plate) delamination. Pro‐plate delamination is favored by low convergence rates, high lithospheric density, and relatively strong retro‐plate, whereas retro‐plate delamination requires a weak retro‐plate. The Northern Apennines and Central Northern Tibetan Plateau are possible geological analogs for the pro‐plate and retro‐plate delamination modes, respectively. Our model also shows significant impact of delamination on the topographic evolution of orogens. Large‐scale lithosphere delamination in continental collision zones would lead to wide and flat plateaus, whereas relatively narrow and steep mountain belts are predicted in orogens without major delamination.

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New evidence of delamination in the Western Alboran Sea

Cited by 9 publications

References 44 publications

Coulomb Stress Perturbations Related to the Al Hoceima (Morocco) Earthquakes of 1994 and 2004

Coulomb Stress Perturbations Related to the Al Hoceima (Morocco) Earthquakes of 1994 and 2004

Crustal Attenuation Tomographic Image of Northern Morocco: Indication of High Tectonic Activities

Lithosphere delamination in continental collisional orogens: A systematic numerical study

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