Neo-deterministic seismic hazard assessment in North Africa

Mourabit, Taoufik; Elenean, K. M. Abou; Ayadi, Abdelhakim; Benouar, Djillali; Suleman, abdunnur Ben; Bezzeghoud, Mourad; Cheddadi, A.; Chourak, Mimoun; Gabry, Mohamed El; Harbi, Assia; Hfaiedh, M.; Hussein, H. M.; Kacem, J.; Ksentini, Ahmed; Jabour, Nacer; Magrin, Andrea; Maouche, Saïd; Meghraoui, Mustapha; Ousadou, Farida; Panza, G. F.; Peresan, Antonella; Romdhane, Najla Bouden; Vaccari, Franco; Zuccolo, Elisa

doi:10.1007/s10950-013-9375-2

Cited by 55 publications

(21 citation statements)

References 106 publications

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“…It is an in-progress study (Ruggieri et al 2012) in collaboration with research institutions in India (Institute of Seismological Research, Gujarat and Centre for Mathematical Modelling and Computer Simulation, Bangalore), and there are advanced-stage pilot projects in several countries (e.g. Mourabit et al 2014).…”

Section: Why Ndsha Has Been Developed In Italy Firstmentioning

confidence: 99%

Seismic waves in 3-D: from mantle asymmetries to reliable seismic hazard assessment

Panza

Romanelli

2014

Earthq Sci

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A global cross-section of the Earth parallel to the tectonic equator (TE) path, the great circle representing the equator of net lithosphere rotation, shows a difference in shear wave velocities between the western and eastern flanks of the three major oceanic rift basins. The lowvelocity layer in the upper asthenosphere, at a depth range of 120 to 200 km, is assumed to represent the decoupling between the lithosphere and the underlying mantle. Along the TE-perturbed (TE-pert) path, a ubiquitous LVZ, about 1,000-km-wide and 100-km-thick, occurs in the asthenosphere. The existence of the TE-pert is a necessary prerequisite for the existence of a continuous global flow within the Earth. Ground-shaking scenarios were constructed using a scenario-based method for seismic hazard analysis (NDSHA), using realistic and duly validated synthetic time series, and generating a data bank of several thousands of seismograms that account for source, propagation, and site effects. Accordingly, with basic selforganized criticality concepts, NDSHA permits the integration of available information provided by the most updated seismological, geological, geophysical, and geotechnical databases for the site of interest, as well as advanced physical modeling techniques, to provide a reliable and robust background for the development of a design basis for cultural heritage and civil infrastructures. Estimates of seismic hazard obtained using the NDSHA and standard probabilistic approaches are compared for the Italian territory, and a case-study is discussed. In order to enable a reliable estimation of the ground motion response to an earthquake, three-dimensional velocity models have to be considered, resulting in a new, very efficient, analytical procedure for computing the broadband seismic wave-field in a 3-D anelastic Earth model.

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Section: Why Ndsha Has Been Developed In Italy Firstmentioning

confidence: 99%

Seismic waves in 3-D: from mantle asymmetries to reliable seismic hazard assessment

Panza

Romanelli

2014

Earthq Sci

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“…Therefore, a significant probability of damage can be expected even in the case of not excessively severe earthquakes. Since the 2004 earthquake, seismologists became more interested in seismic hazard in the region (Ait Brahim et al 2004;Mourabit et al 2013). However, the same cannot be said about seismic vulnerability, which is a relatively new field, to what it hasn't been given the proper attention it deserves, hence the importance of this study.…”

Section: Manuscriptmentioning

confidence: 98%

Seismic risk in the city of Al Hoceima (north of Morocco) using the vulnerability index method, applied in Risk-UE project

et al. 2016

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The final publication is available at Springer via http://dx.doi.org/10.1007/s11069-016-2566-8Al 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.Peer ReviewedPostprint (author's final draft

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“…Although the seismic hazard in Morocco is not as important as in other Mediterranean countries like Italy, Turkey or Greece, it is far from being negligible. Indeed, the relatively superficial nature of the seismicity may combine with weak ground mechanical properties to induce relatively strong accelerations that may lead to significant damage to buildings that do not always meet construction standards (Mourabit et al, 2014). During the last decades, Morocco suffered from several destructive earthquakes such as the Mw 5.9 Agadir event in 1960 or more recently those that struck the region of Al Hoceima in 1994 (M w 5.7), 2004 (M w 6.3), and 2016 (M w 6.3).…”

Section: Active Tectonics Of Northern Moroccomentioning

confidence: 99%

Seismo‐Tectonic Model for the Southern Pre‐Rif Border (Northern Morocco): Insights From Morphochronology

et al. 2021

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In intraplate tectonic regions characterized by moderate seismic activity, the recognition of active zones of deformation has long been a challenging task (e.g., Landgraf et al., 2017). Like Northern Africa, such regions are generally characterized by low hazard but high risk due to the concentrations highly vulnerable population and/or infrastructures (Moreno et al., 2004). Moreover, when low strain rates are combined with meteorological and anthropogenic overprints, the geomorphic signatures associated with active faults fade away as fault slip rates decrease. Consequently, diagnostic criteria established in areas of high strain rates may not be effectively applied. Furthermore, low-levels of seismic strain induce low displacement rates, which may be distributed over numerous fault segments rather than localized on a single fault. At the regional scale, such a distribution of the tectonic deformation can also obscure the seismogenic potential of any given single structure, as, for example, the La Rouvière Fault reactivation during the 2019 M w 4.9 Le Teil Earthquake (Ritz et al., 2020), in southeastern France, which was previously considered as inactive (Jomard et al., 2017).Part of the peri-Mediterranean Alpine chain surrounding the Alboran Sea, the Rif Mountain belt in Morocco is an area of moderate tectonic activity. Located within the diffuse convergence zone between the Nubia Abstract Located at the southern boundary of the Alpine chain in Morocco, the deformation front of the Southern Rif Mountains is a region of moderate tectonic activity, which makes it a good natural laboratory to understand whether, and how, low compressional strains are located on specific structures. Along the ≈80 km-long left-lateral, transpressive and reverse fault zone that runs at the toe of the Pre-Rif Ridges, an analysis of high-resolution digital topography provides new geomorphic lines of evidence supporting Quaternary activity along, 20 km-long fault segments. The fault zone can be divided into the Meknès and the Fès segments, which are constrained at depth by reactivated, NE-trending basement faults, delimitating paleo-grabens associated with the Late Triassic-Jurassic opening of the Atlantic Ocean. For selected sites, we used in situ-produced 36 Cl, 10 Be, and 26 Al and high-resolution topography to infer the timing of abandonment of fluvial markers, which suggest incision rates on the order of 0.6-2 mm/yr. Given their lengths, scaling laws suggest that the identified fault segments should root at about 7-12 kmdepth, possibly reactivating former basement normal faults and making them potential seismogenic sources capable of generating M w 6+ earthquakes, with return times of the order of several hundreds of years. Our new morphochronological data set confirms that the Southern Rif deformation front is a key structure that may have accommodated most of the lateral extrusion of the Rif between the Nubia and Iberia tectonic plates.Plain Language Summary In Morocco, the population may suffer from the dramatic consequences of ...

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Neo-deterministic seismic hazard assessment in North Africa

Cited by 55 publications

References 106 publications

Seismic waves in 3-D: from mantle asymmetries to reliable seismic hazard assessment

Seismic waves in 3-D: from mantle asymmetries to reliable seismic hazard assessment

Seismic risk in the city of Al Hoceima (north of Morocco) using the vulnerability index method, applied in Risk-UE project

Seismo‐Tectonic Model for the Southern Pre‐Rif Border (Northern Morocco): Insights From Morphochronology

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