Tectonic and hydrodynamic control of landslides in the northern area of the Central Rif, Morocco

The northern edge of the Central Rif (Morocco) is subject to numerous landslides where mechanisms do not correspond to the classical models used by geomechanics specialists. It is necessary to adopt a multidisciplinary approach that combines geomorphology, geology, hydrogeology, and geotechnics in order to understand how such slope failures are generated, especially in a region with a heterogeneous structure characterised by significant lithological differences, severe fracturing, and thrust sheets where tectonic contacts play a major role in groundwater circulation. This report shows that these failures are essentially controlled by the tectonic contact separating the Tisirene and Chouamat thrust sheets and by subsurface hydrodynamic conditions. A model of spatial and temporal variations in the factor of safety is proposed.     

Probabilistic seismic hazard zonation of Syria

Earthquake hazard maps for Syria are presented in this paper. The Peak Ground Acceleration (PGA) and the Modified Mercalli Intensity (MMI) on bedrock, both with 90% probability of not being exceeded during a life time of 50, 100 and 200 years, respectively are developed. The probabilistic PGA and MMI values are evaluated assuming linear sources (faults) as potential sources of future earthquakes. A new attenuation relationship for this region is developed. Ten distinctive faults of potential earthquakes are identified in and around Syria. The pertinent parameters of each fault, such as theb-parameter in the Gutenberg-Richter formula, the annual rate ₄ and the upper bound magnitudem ₁ are determined from two sets of seismic data: the historical earthquakes and the instrumentally recorded earthquake data (AD 1900–1992). The seismic hazard maps developed are intended for preliminary analysis of new designs and seismic check of existing civil engineering structures.     

Removal of chromium (VI) from aqueous solutions using Lewatit FO36 nano ion exchange resin

The removal of the chromium (VI) ion from aqueous solutions with the Lewatit FO36 ion-exchange resin is described at different conditions. The effects of adsorbent dose, initial metal concentration, contact time and pH on the removal of chromium (VI) were investigated. The batch ion exchange process was relatively fast and it reached equilibrium after about 90 min of contact. The ion exchange process, which is pH dependent showed maximum removal of chromium (VI) in the pH range 5.0–8.0 for an initial chromium (VI) concentration of 0.5 mg/dm³. The equilibrium related to Lewatit FO36 ion- exchange capacity and the amounts of the ion exchange were obtained using the plots of the Langmuir adsorption isotherm. It was observed that the maximum ion exchange capacity of 0.29 mmol of chromium (VLVg for Lewatit FO36 was achieved at optimum pH value of 6.0. The ion exchange of chromium (VI) on this cation-exchange resin followed first-order reversible kinetics.     

Porosity and hydraulic conductivity estimation of the basaltic aquifer in Southern Syria by using nuclear and electrical well logging techniques

An alternative approach using nuclear neutron-porosity and electrical resistivity well logging of long (64 inch) and short (16 inch) normal techniques is proposed to estimate the porosity and the hydraulic conductivity (K) of the basaltic aquifers in Southern Syria. This method is applied on the available logs of Kodana well in Southern Syria. It has been found that the obtained K value by applying this technique seems to be reasonable and comparable with the hydraulic conductivity value of 3.09 m/day obtained by the pumping test carried out at Kodana well. The proposed alternative well logging methodology seems as promising and could be practiced in the basaltic environments for the estimation of hydraulic conductivity parameter. However, more detailed researches are still required to make this proposed technique very performed in basaltic environments.     

Accounting for Depletion of Oil and Gas Resources in Malaysia

Since oil and gas are non-renewable resources, it is important to identify the extent to which they have been depleted. Such information will contribute to the formulation and evaluation of appropriate sustainable development policies. This paper provides an assessment of the changes in the availability of oil and gas resources in Malaysia by first compiling the physical balance sheet for the period 2000–2007, and then assessing the monetary balance sheets for the said resource by using the Net Present Value method. Our findings show serious reduction in the value of oil reserves from 2001 to 2005, due to changes in crude oil prices, and thereafter the depletion rates decreased. In the context of sustainable development planning, albeit in the weak sustainability sense, it will be important to ascertain if sufficient reinvestments of the estimated resource rents in related or alternative capitals are being attempted by Malaysia. For the study period, the cumulative resource rents were to the tune of RM61 billion. Through a depletion or resource rents policy, the estimated quantum may guide the identification of a reinvestment threshold (after considering needed capital investment for future development of the industry) in light of ensuring the future productive capacity of the economy at the time when the resource is exhausted.     

Statistical landslide susceptibility assessment of the Mansehra and Torghar districts,Khyber Pakhtunkhwa Province,Pakistan

This paper presents laboratory experiments and numerical simulations of effects of submerged obstacles on tsunami-like solitary wave and its run-up. This study was carried out for the breaking and non-breaking solitary waves on 1:19.85 uniform slope which contains a submerged obstacle. New laboratory experiments are performed to describe the mitigation of tsunami amplitude and run-up under the effect of submerged obstacles. We are based on experimental results obtained to validate the numerical model. The numerical modeling using COULWAVE aims essentially to show the effect of the obstacle on the shape of solitary wave and the limit of this effect. Using a multiple nonlinear regression, we have determined a model to estimate height of run-up according to the amplitude of the wave and the obstacle peak depth.     

SWAT‐simulated hydrological impact of land‐use change in the Zanjanrood basin,Northwest Iran

Understanding the impacts of land‐use changes on hydrology at the watershed scale can facilitate development of sustainable water resource strategies. This paper investigates the hydrological effects of land‐use change in Zanjanrood basin, Iran. The water balance was simulated using the Soil and Water Assessment Tool (AVSWAT2000). Model calibration and uncertainty analysis were performed with sequential uncertainty fitting (SUFI‐2). Simulation results from January 1998 to December 2002 were used for parameter calibration, and then the model was validated for the period of January 2003 to December 2004. The predicted monthly streamflow matched the observed values: during calibration the correlation coefficient was 0·86 and the Nash–Sutcliffe coefficient 0·79, compared with 0·80 and 0·79, respectively, during validation. The model was used to simulate the main components of the hydrological cycle, in order to study the effects of land‐use changes in 1967, 1994 and 2007. The study reveals that during 1967 a 34·5% decrease of grassland with concurrent increases of shrubland (13·9%), rain‐fed agriculture (12·1%), bare ground (5·5%) irrigated agriculture (2·2%), and urban area (0·7%) led to a 33% increase in the amount of surface runoff and a 22% decrease in the groundwater recharge. Furthermore, the area of sub‐basins that was influenced by high runoff (14–28 mm) increased. The results indicate that the hydrological response to overgrazing and the replacing of rangelands (grassland and shrubland) with rain‐fed agriculture and bare ground (badlands) is nonlinear and exhibits a threshold effect. The runoff rises dramatically when more than 60% of the rangeland is removed. For groundwater this threshold lies at an 80% decrease in rangeland. Copyright © 2009 John Wiley & Sons, Ltd.     

De nouveaux éléments structuraux du complexe aquifère profond du bassin du Rharb (Maroc) : implications hydrogéologiques

The Rharb basin is located in northwestern Morocco. It is a part of one of the most important hydrogeological basins of Morocco, and extends over some 4000 km². The nature of its Plio-Quaternary sedimentary fill and its structural and palaeoenvironmental contexts are reflected by great variations in aerial and temporal facies distribution. This distribution, in turn, is a direct cause of the observed complexity in the geometry of potentially water-bearing beds. In the present work, we present an image of potential new hydrogeological reservoirs and define new structures that partially explain their architecture. To cite this article: M. Kili et al., C. R. Geoscience 338 (2006).