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Rockfall simulations constitute the first step toward hazard assessments and can guide future rockfall prevention efforts. In this work, we assess the impact of digital elevation model (DEM) resolution on the accuracy of numerical rockfall simulation outputs. For this purpose, we compared the simulation output obtained using 1 m, 2 m and 3 m resolution UAV-derived DEMs, to two other models based on coarser topographic data (a 5 m resolution DEM obtained through interpolating elevation contours and the Shuttle Radar Topographic Mission 30m DEM). To generate the validation data, we conducted field surveys in order to map the real trajectories of three boulders that were detached during a rockfall event that occurred on 1 December 2018. Our findings suggest that the use of low to medium-resolution DEMs translated into large errors in the shape of the simulated trajectories as well as the computed runout distances, which appeared to be exaggerated by such models. The geometry of the runout area and the targets of the potential rockfall events also appeared to be different from those mapped on the field. This hindered the efficiency of any prevention or correction measures. On the other hand, the 1m UAV-derived model produced more accurate results relative to the field data. Therefore, it is accurate enough for rockfall simulations and hazard research applications. Although such remote sensing techniques may require additional expenses, our results suggest that the enhanced accuracy of the models is worth the investment.

Rockfalls can cause loss of life and material damage. In Northern Morocco, rockfalls and rock avalanche-deposits are frequent, especially in the Dorsale Calcaire morpho-structural unit, which is mostly formed by Jurassic limestone and dolostone formations. In this study, we focus exclusively on its northern segment, conventionally known as “the Haouz subunit”. First, a rockfall inventory was conducted. Then, two datasets were prepared: one covering exclusively the source area and the other representing the entirety of the mass movements (source + propagation area). Two algorithms were then used to build rockfall susceptibility models (RSMs). The first one (Logistic Regression: LR) yielded the most unreliable results, where the RSM derived from the source area dataset significantly outperformed the one based on the entirety of the rockfall affected area, despite the lack of significant visual differences between both models. However, the RSMs produced using Artificial Neural Networks (ANNs) were more or less similar in terms of accuracy, despite the source area model being more conservative. This result is unexpected given the fact that previous studies proved the robustness of the LR algorithm and the sensitivity of ANN models. However, we believe that the non-linear correlation between the spatial distribution of the rockfall propagation area and that of the conditioning factors used to compute the models explains why modeling rockfalls in particular differs from other types of landslides.

The Pre-Rif Ridges constitute the southward deformation front of the entire Rif chain, Northern Morocco. Previous investigations showed that evidence in favor of active, recent and neotectonic deformation can be found all over this area. However, the effect of such tectonic activity on surface processes such as gullying and land-sliding was never properly investigated. Therefore, we conducted a statistical analysis using different statistical approaches (comparison tests, frequency-area distributions, frequency ratio) to compare three zones of the study area, with different tectonic attributes (zone A: inactive tectonic processes, zone B: neotectonic deformation and zone C: active tectonic deformation). The first zone (A), which presents little to no evidence of intense deformation, is shown to be very different to the other two areas both in terms of landslides and gully morphometries. It has also gentler slopes which promote less landslides in marly terrains as shown by the factor of safety analyses conducted in this study. The other two segments of the study area are more or less similar with relatively steeper topographies and a higher density of mass movements. Given that both zones are relatively intensely deformed compared to zones 1, one can attribute the abundance of surface processes in these two areas to the tectonic uplift and topographic growth, which play a major role in promoting such processes.

In Northern Morocco, seismic site-effects in general and liquefaction hazard in particular can occur in the event of a major earthquake due to the thick sedimentary cover characterizing the peripheral Neogene basins of the Alboran Sea. An example is Martil plain, which was the subject of important economic development during the last two decades. In this regard, we present in this study an assessment of seismic site-effect hazard through the horizontal-to-vertical spectral ratio (HVSR) method and the vulnerability index (Kg). Multiple Analysis of Surface Waves (MASW) method and core-drilling data are also used to complete our analysis and interpret the spatial distribution of Kg maps. Our findings suggest more vulnerability to liquefaction in the Southern segment of the basin, which can be explained by the asymmetrical geometry of Quaternary sedimentation, due to tectonic uplift that influences also the surface and subsurface hydrology processes. However, in this study, the main difficulties and the challenges that we faced were related to data acquisition during windy days and in the areas near industrial zones or near high traffic roads, which have significant effects on the accuracy of the HVSR analysis. In this study, HVSR microtremor measurements are recorded at 197 stations in the Martil floodplain to generate a seismic vulnerability index (Kg) map. According to the analysis results, the predominant frequency (F0) values range from about 0.2 to 10.6 Hz and the peak amplitudes (A0) values are in the range of 0.39–10.4. As a result, some districts, especially those classified as economically disadvantaged, are found to be the most exposed to this hazard (with a Kg > 10), which must be taken into consideration in future risk reduction and mitigation plans. We conclude the existence of significant seismic effects potential despite the moderate seismicity of the area. Therefore, our research needs to be completed by scenario-based seismic hazard modeling to investigate the capacity of seismic events at the region to produce the above-suggested amplifications.

Many old and recent landslides affect the Rif region in Northern Morocco. In Chefchaouen city, this natural hazard constitutes a major obstacle for the development of the city and its suburban districts. In this study, a landslide inventory was realized to identify and characterize slope instability cases in the Chefchaouen city, their relationship to the subsoil layers and their effect on the stability of newly built districts. Special attention was given to a recent landslide in the Ain Haouzi district, reactivated in 2016 and causing damage to 35 houses. This slide was subject to further scientific investigations (borehole inclinometer and ERT) in order to better our understanding of the slopes instability in the study area. The results show that the territory of Chefchaouen city which covers an area 23.63 km2 is affected by 447 landslides most of which (300) are very old and inactive. However, many of the old landslide masses and/or scarps were partially reactivated in the last decade, which caused a lot of material damage to many constructions, estimated to be 25.74 M MAD (approximately 2.5 M$). The building damage inventory also showed how the distribution of landslides in the newly constructed suburban/semirural districts is clearly correlated with the spatial distribution of severely damaged houses. For geomorphological reasons, these housing developments prefer terrains mainly formed by weathered clay layers and scree deposits, characterized by weak geotechnical characteristics, which compromises the stability of constructions. The clandestine nature of the construction work (absence of a sewage network, random changes to the topography) increases the vulnerability of buildings to the natural slope dynamics. The layers which constitute the body of most old and recent landslides are subject to slow gravitational deformation which can be accelerated in major rain events. This was the case for the 2016 event which was reactivated by seven consecutive rainy days. The ERT profiles executed in this area coupled with borehole inclinometer results demonstrate that the plastic, weathered clay layers facilitated the slide of the scree deposits, which constitute the landslide’s body. Indeed, the development plan of the city must be adapted to the slope dynamics and the subsoil behavior, so as to avoid unnecessary material damage from taking place in the future.

Quarries are very abundant in Tetouan and Fahs-Anjra provinces as well as in the M’diq-Fnideq prefecture of Northern Morocco. Their growth is proportional to that of the economic development of the region, which has accelerated during the last two decades. However, quarrying practices are largely uninvestigated and their future is still uncertain, especially concerning their environmental sustainability and economic profitability. Therefore, we followed an integrated approach using field investigations and a multicriteria decision-making technique to propose a quarry suitability map of the study area. Unlike some previous research, the weighing of factors and criteria was established through deterministic approaches and field investigations, which include both the quality of the exploitable materials and the environmental impact of quarries into the suitability index formula. Our findings show that only an area equivalent to 1.6 km 2 is suitable for an environmentally friendly, economically profitable, and high-quality aggregate quarry. A larger segment of 54 km 2 could also be the subject of limited and careful exploitation practices, with more pronounced but manageable environmental impacts. The poor management of current quarrying sites is also discussed, which shows that unless some poor practices are avoided, the performance of the suitability index proposed in this research will not be as forecasted by the authors. In fact, for the suitability index to accurately predict the environmental and economic sustainability of future pits, quarry companies must respect the current laws and guidelines, and be willing to interact and participate in the sustainability of geomaterial exploitations for future generations.

The Atlantic coasts of Morocco are exposed to tsunami risk. Although this risk level is low because of the rarity of tsunamis in the region, a future event would be catastrophic for the Moroccan society and economy because of the numerous issues at stake. In this paper, bathymetric/topographic data and parameters of three known tsunamigenic faults (Marquês do Pombal Fault, Gorringe Bank Fault and Horseshoe Fault) were used to simulate a potential tsunami event in the city of El-Jadida (Morocco) using MIRONE software. The simulation results of the worst-case scenario were then exploited to perform a quantitative risk assessment, using demographic and economic input data. Results show that choosing the Horseshoe Fault as source of the simulated event produces the largest tsunamis; with maximum wave heights ranging from 10 to 27 m. These results are found to be consistent with historical records and computer model simulations from previous studies. Quantitative risk assessment results indicate that the city of El-Jadida is exposed to a high risk of loss of lifes and loss of property with values of the order of 34 lives/year and 14 M$/year, respectively. For this reason, we underline the dire need for the implementation of tsunami risk prevention and mitigation strategies that should prioritize the protection of high-risk areas of the city and its population from a possible future catastrophic event.

The Rif Mountains in northern Morocco are highly exposed to geohazards, particularly earthquakes and mass movements. In this context, the Zoumi region is most affected, showing various mass movement types involving both unconsolidated and solid materials. This study evaluates the region’s susceptibility to mass movements using logistic regression (LR), applied for the first time in this area. The model incorporates eight key predisposing factors known to influence mass movement: slope gradient, slope aspect, land use, drainage density, elevation, lithology, fracturing density, and earthquake isodepths. Historical mass movements were mapped using remote sensing and field surveys, and statistical analysis calculation was conducted to analyze their spatial correlation with these environmental conditioning factors. A mass movement susceptibility (MMS) map was produced, classifying the region into four susceptibility levels, ranging from low to very high. Landslides were the most frequent movement type (36%). The LR model showed strong predictive performance, with an AUC of 88%, confirming its robustness. The final map reveals that 42% of the Zoumi area falls within the high to very high susceptibility zones. These results highlight the importance of using advanced modeling approaches to support risk mitigation and land use planning in environmentally sensitive mountain regions.

Marine algae are renowned for their health benefits due to the presence of functional bioactive compounds. In this context, this study aims to valorize the extract of a seaweed, Dictyota dichotoma (D. dichotoma), through phytochemical characterization using liquid chromatography–mass spectrometry (HPLC-MS), as well as in vitro and in silico evaluation of its biological activities (antioxidant and antimicrobial). Phytochemical characterization revealed that the ethanolic extract of Dictyota dichotoma (DdEx) is rich in phenolic compounds, with a total of 22 phycocompounds identified. Antioxidant activity, measured by various methods, showed an IC50 of 120 µg/mL for the DPPH assay, an EC50 of 120.53 µg/mL for the FRAP assay, and a total antioxidant power of 685.26 µg AAE/mg according to the phosphomolybdate (TAC) method. Evaluation of antibacterial activity showed a zone of inhibition diameter ranging from 11.93 to 22.58 mm, with the largest zone observed for the Escherichia coli (E. coli) strain. For antifungal activity, inhibition zone diameters ranged from 22.38 to 23.52 mm, with the largest recorded for the Saccharomyces cerevisiae (S. cerevisiae) strain. The in silico study identified tetragalloyl-glucose, apigenin-7-O-glucoside, and pentagalloyl-glucose as the most active compounds against NADPH oxidase, with docking scores of −7.723, −7.424, and −6.402 kcal/mol, respectively. Regarding antibacterial activity, apigenin-7-O-glucoside, pelargonidin-3-O-glucoside, and secoisolariciresinol demonstrated high affinity for E. coli beta-ketoacyl-[acyl carrier protein] synthase, with docking scores of −7.276, −6.811, and −6.594 kcal/mol, respectively. These in vitro and in silico evaluations showed that D. dichotoma extract possesses antioxidant and antimicrobial properties, due to its richness in bioactive compounds identified by HPLC.