On a damaging earthquake-induced landslide in the Algerian Alps: the March 20, 2006 Laâlam landslide (Babors chain,northeast Algeria), triggered by the Kherrata earthquake (<Emphasis Type="Italic">M</Emphasis><Subscript>w</Subscript> = 5.3)     

Mehdi A. Guemache  Djamel Machane  Hamoud Beldjoudi  Sofiane Gharbi  Leila Djadia  Sihem Benahmed  Hayet Ymmel 《Natural Hazards》2010,54(2):273-288

On March 20, 2006, an earthquake (M _w = 5.3; SED) struck the mountainous region of the Babors chain (Wilaya of Bejaia, northeast Algeria). The seismic epicenter was located near the Kherrata village. This earthquake was felt on a large area of the northeastern part of Algeria. It reached an intensity of VII (EMS scale) at the Laalam village, situated at about 20 km northeast of Kherrata. Here, many old and recent houses were damaged or collapsed totally, four people died and 68 were injured. Field investigations revealed that these casualties were caused by a landslide triggered by the earthquake. Many fissures were visible on ground throughout the site. They were generated by both sliding and settling phenomena. The Laalam site is prone to landslide, as revealed by some evidences on old instabilities. This is due to two main factors: local geomorphology and geology. These factors intervene synchronously for reducing the slope instability at the Laalam village. The March 20, 2006 Kherrata earthquake was the trigger that released the Laalam landslide.  相似文献   

Metal fluxes to the sediments of the Moulay Bousselham lagoon,Morocco   总被引：2，自引：0，他引：2  

Asmae Mhamdi Alaoui  Mohamed Choura  Mohamed Maanan  Bendahhou Zourarah  Marc Robin  Maria Freitas Conceição  César Andrade  Mehdi Khalid  Christian Carruesco 《Environmental Earth Sciences》2010,61(2):275-286

The metal content in surface sediments (0–2 cm, 26 samples), in a sediment core (120, 1 cm slices), taken from Moulay Bousselham (Morocco) was investigated. Concentrations of Al, Fe, Mn, Pb, Zn, Cu, Ni, Cr, Cd, As, and Hg were evaluated in surface and cored sediments of Moulay Bousselham lagoon. Significantly high concentrations in μg g⁻¹ dw of Pb (31.7–6.2), Zn (758.9–167), Cu (310.7–22), Ni (96–10.5), Cr (113–18.9), Cd (0.84–0.02), As (1–0.1), and Hg (0.61–0.02) were found in sediment samples from Moulay Bousselham lagoon. Calculated enrichment factors [EF_Me = (Me/Al)_sample/(Me/Al)_background], using Al as a normalizer, and correlation matrices showed that metal pollution in Merja Zerga of Moulay Bousselham lagoon was the product of anthropogenic sources, while the metal content in Merja Kehla was of natural origins. The results suggest that a major change in the sedimentary regime of the lagoon, associated with internal trapping and re-distribution of heavy metal, has been occurring in the past few decades. The cause would appear to be the construction of a Nador Canal at the lagoon. Probable effects concentrations (PEC) were often exceeded for heavy metals in the lagoon sediments, especially for Zn, Cu, Ni, and Cr, and four stations, stations MZ-11, MZ-12, MZ-13, MZ-14, MZ-16, and MZ-17, had multiple metals at presumptively toxic levels. These comparisons suggest that sediment metal levels in the river are clearly high and probably pose an environmental risk at some stations. The levels of most of the metals were not greatly enriched, a consideration that is of the utmost importance when contamination issues are at stake. Metal concentrations found in Moulay Bousselham lagoon were comparable to aquatic systems classified as contaminated from other regions of the world.  相似文献   

Evidence for an underground runoff and soil permeability at the Ouled Fayet (Algiers,Algeria) subsurface landfill pilot project from geophysical investigations   总被引：1，自引：1，他引：0  

Leila Djadia  Djamel Machane  Jean-Luc Chatelain  Abdesslam Abtout  Rabah Bensalem  Mehdi Amine Guemache  Bertrand Guillier  Amar Boudella  El-Hadi Oubaiche 《Environmental Earth Sciences》2010,59(5):1149-1158

Results from geophysical investigations (electrical resistivity, electromagnetic mapping and seismic refraction) on an excavated cell of the Ouled Fayet (Algiers, Algeria) pilot landfill indicated the presence of an underground runoff and permeable soil underneath the cell. These results contradict those obtained by a feasibility study, based, however, only on the analysis of seventy-six 10-m drilling cores. The 1D boreholes information has been proven to be insufficient and to give biased results. The presence of water at depth is evidenced by lower resistivity, high conductivity anomalies and increase of P-wave velocity. Thus, to the contrary of what is claimed in the feasibility study, a threat of leachate pollution is real. This study shows that landfill construction studies cannot give trustful results without geophysical investigations. More specifically, in Algeria, it is imperative to elaborate a landfill construction code, which should include mandatory geophysical prospecting and deeper drilling cores.  相似文献   

X-ray determination and equilibrium composition of clinopyroxenes in the system CaO-MgO-Al2O3-SiO2     

Piera Benna  Emiliano Bruno  Aurelio Facchinelli 《Contributions to Mineralogy and Petrology》1982,78(3):272-278

Ternary clinopyroxenes have been synthesized in the plane Di-CaTs-En. The variation of their crystallographic parameters has allowed the development of three determinative grids, which utilize b-, 2 _22¯1–2 ₃₁₀ and 2 ₃₃₀ –2 ₂₀₂ respectively. These grids show significant differences in comparison with the previously proposed ones. Present results have been used to review some data on clinopyroxenes equilibria in the system CaO-MgO-Al₂O₃-SiO₂ (CMAS) (Biggar 1969; Bruno and Facchinelli 1978; Herzberg 1978; O'Hara and Schairer 1963; Boyd 1969). In particular the petrogenic grid correlating P, T and CaTs content of clinopyroxenes in spinel-lherzolite assemblage (Herzberg 1978) has been revised, and consequently equilibrium temperatures rise by one hundred degrees.  相似文献   

Erratum à la note Rôle de l&#x27;halocinèse dans l&#x27;évolution du bassin d&#x27;Essaouira (Sud-Ouest marocain) [C. R. Geoscience 336 (2004) 587–595]     

Khalid Mehdi  Roger Griboulard  Claude Bobier 《Comptes Rendus Geoscience》2005,337(9):880

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Average structure and M2 site configurations in C2/c clinopyroxenes along the Di-En join     

M. Tribaudino  P. Benna  E. Bruno 《Contributions to Mineralogy and Petrology》1989,103(4):452-456

In order to clarify the structural configurations observed in Di_ss in the Ca-rich region of the Di-En join (in which TEM observations show neither exsolution microstructures nor evidence of spinodal decomposition) single crystals large enough for X-ray diffraction analyses, with composition (Ca_0.66Mg_0.34)MgSi₂O₆, have been equilibrated close to the solvus atT=1350° C for 317 h, and quenched at room temperature. The refinement in C2/c space group shows that in the M2 site Ca and Mg are fully ordered in two split positions (M2_occ: 0.66 Ca; M2_occ: 0.34 Mg). Since the average structure shows a relevant elongation of anisotropic thermal ellipsoids of the O2 and O3 oxygen atoms, the refinement has been carried out according to a split model for O2 and O3 atoms: Ca appears 8-coordinated (as in diopside) and Mg shows a sixfold coordination similar to that of high-pigeonite. This coordination for Mg is significantly different from the fourfold coordination (Zn-like in Zn-cpx) proposed previously and it is a more probable coordination for Mg from a crystalchemical point of view. The same results were obtained refining a Di₈₀En₂₀ cpx, equilibrated atT=1230° C, according to the same O-split model. The data support the coexistence of a Di-like configuration for Ca and of a highPig-like configuration for Mg away from the solvus also. AtT very near toT _solidus the different configurations, observed at room temperature in the quenched samples, should converge and Ca and Mg should retain a single disordered configuration in the M2 site.  相似文献   

First Research on Marine and Nonmarine Sedimentary Sequences and Micropaleontologic Significance across Permian／Triassic Boundary in Iran （Isfahan and Abadeh）     

MehdiYazdi ManizhehShirani 《中国地质大学学报(英文版)》2002,13(2):T002-T006

Abundant ichthyoid remains, conodonts and holothurians sclerites were recovered near the Permian/Triassic boundary from a section south of Isfahan. Recovered ichthyoid remains include shark micro teeth and scales. The ichthyolith material is similar to a Fasanian ichthyolith from the Zakazane area in the Slovak karst of the Western Carpathians, which represents a subspecies of Acodina triassia. Conodont species are mostly neogondolellids. This fauna indicates that the sedimentary environment was marine, while to the north of localities near Isfahan and Zagross, terrestrial deposition was dominant at that time. Aluminasilicate and kaolin are present in a continental unit in Dopolan refractory main (Shahid Nilchian mine) and a section south of Chahriseh Village, north of Isfahan. Pisolitie, ironstone facies and bauxite clay are common near the Permian/Triassic boundary in the Chahriseh region.  相似文献   

Strong motion dataset of Turkey: data processing and site classification     

Mehdi Zar  Pierre-Yves Bard 《Soil Dynamics and Earthquake Engineering》2002,22(8)

Strong motion records of Turkey are studied in order to prepare a catalog to be used as a database for further studies (for instance empirical attenuation laws). The network started to be installed in 1973, and the first record was obtained in 1976. The instruments are of SMA-1 analog recorders and SIG SM-2 and GeoSys GSR-16 digital types. Out of a total of 426 records released on the web sites of the General Directorate of the Disaster Affairs and of Kandili Observatory, a set of 210 records was selected with a satisfactory quality, for which it was possible to associate correctly determined source parameters (source magnitudes and epicentral distances). Most of the records are obtained from around North and East Anatolian Fault zones, as well as from western and southwestern parts of Turkey. The main outcome of this paper is a strong motion catalog of Turkey, with the indication of site conditions, of the frequency band of the reliability of the records, peak values of acceleration, velocity and displacements, source parameters (magnitude, epicentral and macroseismic distances), intensity and finally the fault plane solutions whenever possible. The aim is to have, with other regional dataset, a homogenous and good quality dataset.  相似文献   

Inhomogeneous shearing related to rock composition: evidence from a major late-Panafrican shear zone in the Tuareg shield (Algeria)     

Bernard Henry  Mohamed E. M. Derder  Boualem Bayou  Mehdi A. Guemache  Omar Nouar  Aziouz Ouabadi  Hamou Djellit  Mohamed Amenna  Abderahmane Hemmi 《Swiss Journal of Geoscience》2008,101(2):453-464

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Thermodynamic behaviour of the high-temperature P\bar 1{\text{-}}I\bar 1 phase transition along the CaAl2Si2O8–SrAl2Si2O8 join     

M. Tribaudino  P. Benna  F. Nestola  C. Meneghini  E. Bruno 《Physics and Chemistry of Minerals》2005,32(4):314-321

In situ high-temperature synchrotron radiation powder diffraction patterns were taken from room temperature to T = 740°C from synthetic feldspars along the join CaAl₂Si₂O₈–SrAl₂Si₂O₈ (An–SrF). Three samples of composition An₉₅SrF₅, An₉₀SrF₁₀ and An₈₅SrF₁₅ were investigated, and the evolution of cell parameters with T was determined by Rietveld analysis of powder X-ray diffraction patterns. The high-temperature $P\bar 1{\text{-}}I\bar 1$ phase transition, previously observed with T _c = 241°C in anorthite, was found in An₉₅SrF₅, An₉₀SrF₁₀ and An₈₅SrF₁₅ feldspars at T _c = 233(5)°, 195(2)° and 174(2)°C respectively. The transition was revealed by the disappearance of critical reflections and variations in the rate of change of cell parameters with temperature. A significant, although small (between 0.0025 and 0.0012 at room temperature), spontaneous strain could be measured, allowing the thermodynamic behaviour of the transition to be modelled. A second-order trend for An₉₀SrF₁₀ and An₈₅SrF₁₅ [β = 0.504(7) and 0.505(7) respectively] or nearly second-order for An₉₅SrF₅[β = 0.458(4)] was observed in contrast with tricritical behaviour of end member anorthite. An extrapolation of the T _c versus composition to room temperature indicates that the critical composition for the $P\bar 1$ phase is An₆₀SrF₄₀.  相似文献