Slope stability analyses and geological risk reduction: two case studies, from engineering-geological characterization to rockfall runout modeling with intervention proposal

Rock slope instability is a major risk to human life, often leading to economic losses, property damage and maintenance costs, as well as injuries or death. Because the rock mass behavior is significantly governed by the presence of joints or other discontinuities, several types of slope failure such as plane failure, toppling failure, wedge failure, buckling failure and circular failure are often observed. These failures may be gradual with very slow movement of the sliding block or instantaneous without much warning. To understand this process, it is important to study the rock slope (geological data collections, geotechnical collections, data kinematic stability analysis, runout analyses…) This work is divided in two cases of studies, which are both complementary to study a rock slope stability: 1. The first case of study is an underground quarry of marble located in Levigliani (Luca, Italy), which we did a classification of the rockmass based on the empirical method of Bieniawski (RMR) and also a kinematic analysis of the conditions of stability with the software Rocscience Dips, after a 3D stability analysis was used by the software Rocscience Unwedge which was developed specifically for the use in underground rock mining; 2. For the second case of study is an ex open pit quarry of limestone located in Vecchiano (Pisa, Italy), in which we calculated the trajectories of falling blocks with an advanced numerical method (Rockyfor3D): rigid body approach, capable of analyzing the propagation phase of the volumes detached from the slope; methodology that allowed to simulate the rockfall phenomena through the production of block rebound mechanisms during the descent towards the slope and also we gave an intervention proposal to mitigate the risk; the localization and sizing of the blocks was done by a Digital Terrain Model (DTM)

Active faulting and earthquakes in the central Alboran Sea

Central Alboran Sea constitutes a key area to analyze the relationships between active tectonic structures and moderate seismicity. The heterogeneous crustal layered structure and the propagation of the deformation along the fault zones are key features to relate active faults and seismic hazard. The NW-SE oblique convergence between Eurasian and African plates determines the broad band of tectonic deformation and seismicity along the Alboran Sea basin (westernmost Mediterranean). The Betic-Rif Cordilleras are connected through the Gibraltar Arc and surround the Alboran Sea formed by thinned continental crust. This basin is filled since the Neogene by sedimentary and volcanic rocks. Central Alboran Sea is now undergoing shortening and is mainly deformed by a system of conjugated WNW-ESE dextral and NE-SW sinistral faults with recent activity formed by indenter tectonics related to a heterogeneous crustal behavior. In addition a NNW-SSE normal fault set and large ENE-WSW folds deform the central and northern Alboran Sea. These structures support a present-day N160 E maximum compression and orthogonal extension. In this setting, most of the recent seismicity is concentrated along a NNE-SSW zone that extends landward from Campo de Dalias (SE Spain) to Al Hoceima (Morocco). The Campo de Dalias 1993-1994 seismic crisis reached up to magnitudes Mw= 5.3, while the Al Hoceima area was affected by seismic crisis of 1994 (May 26, Mw=5.6) and 2004 (Feb 24, Mw= 6.4). The main active fault related to the 2004 earthquakes, even that it was a vertical NNE-SSW oriented fault and focal depth was 6 km, did not reach the surface probably due to the presence of a mechanically layered crust. The main active surface faults located in Al Hoceima area (the NNE-SSW transtensional sinistral Trougout fault zone) extended northwards towards the NE-SW sinistral Al Idrissi Fault that intersects the Alboran Sea and are connected with the normal NNW-SSE Balanegra Fault zone. Although these active faults determine most of the seismicity of the central Alboran Sea, the seismic crisis that occurred since January 2016, reaching Mw= 6.3 is located in a region westward of Al Idrissi Fault, underlining the relevance of growth of new faults to determine the seismic hazard of the region. Earthquake focal mechanisms support that the main active fault has a NNE-SSW orientation, similar to Al Idrissi Fault zone. Maximum magnitude suggests a surface rupture length of at least 12 km and a subsurface rupture of 20 km. Propagation of a new fault is more efficient to accumulate elastic deformation, and to produce highest magnitude earthquakes than already formed faults. This new fault is connected probably in deep crustal levels with the blind sinistral fault responsible of the 2004 Al Hoceima earthquake. The tsunami hazard of the region should be consequence of both seabottom displacement due to fault activity and co-seismic submarine landslides. The INCRISIS cruise, scheduled by May 2016, will provide evidences of seabottom effects of this seismic crisis

Neogene evolution of the Tetouan-Martil basin; northern Rif, Morocco

Tetouan-MartHpost-nappes basin is opened by two rifting stages: the first in late Oligocene-Burdigalian times, is accompanied by ductile normal faults in Aquitanian-Burdigalian rocks; the second of post Burdigaiian and pre-PHocene age, has produced two low angle norma/ fault systems, trending NE-SW and NW-SE, leading to the collapse of this basinLe bassin de Tétouan-Martil a connu au cours de son histoire géologique deux épisodes de déformations distensives liés à des riftings néogènes de la mer d'Alboran. Le premier, d'âge Oligocène supérieur à Burdigalien, a produit des flexures et des failles normales ductilesfragiles.dans des gneiss et micaschistes.et des failles normales synsédimentaires dans les formations aquitano-burdigalienne

Kinematics and paleostresses in the Jebha-Chrafate transcurrent fault (northern Rif, Morocco)

4 páginas, 3 figuras.-- Trabajo presentado en la 38ª Sesión Científica, Teruel, 2005.The Jebha-Chrafate is an ENE-WSW sinistral major transcurrent fault of the Rif Cordillera, formed during the southwestwards emplacement of the Internal Zones on the Flysch units and the External Zones. The analysis of minor structures along the Jebha area indicates the activity of top to the SW low and high angle normal faults during the tectonic wedge emplacement. In addition, most of the kinematic indicators along the transcurrent fault zone point to a reactivation as dextral fault during the recent NW-SE Eurasia-Africa convergence and a final overprinting of normal faults during the late stages of relief uplift.Este trabajo se ha realizado gracias a la beca postdoctoral concedida al primer firmante por parte de la Agencia Española de la Cooperación Internacional (AECI) 2004-2005. El trabajo ha sido financiado por proyectos de la Consejería de Presidencia (Junta de Andalucia), AECI y BTE 2003-01699 (CICyT).Peer reviewe

Triticum durum var KEBIR

L'objectif de cette recherche est d'étudier l'effet de la salinité du sol par différents niveaux de NaCl (0, 10, 15 g/L) sur certaines propriétés morphologiques et physiologiques du blé dur Triticum durum var KEBIR au stade de la croissance, et la possibilité de le réduire en appliquant une phytohormone la kinétine avec des concentrations (10, 20, 30 mg/L) par pulvérisation foliaire.Les résultats obtenus des propriétés morphologiques montrent que la longueur de la tige et la surface foliaire augmentent proportionnellement avec le degré de la salinité âpres pulvérisation de la kinétine. Concernant les propriétés physiologiques, l'application de cette hormone sur les plantes stressées induit une augmentation proportionnelle de la teneur en chlorophylle (a) et (b) avec la concentration de sel utilisée.Une augmentation de la teneur en proline est observée dans les plantes traitées ou non par l'hormone la kinétine. Mots cles: Salinité- Triticum durum var KEBIR- Phytohormones- Kinétine - Pulvérisation foliaire. The aim of this work is to study the effect of soil salinity using different levels of NaCl (0, 10, 15 g/L) on some morphological and physiological properties of durum wheat Triticum durum var KEBIR in the stage of growth. The possibility to reduce salinity it by one of the phytohormones: kinetin with concentrations of (10, 20, 30 mg/L) through the foliar spray is also studied. The results of morphological properties show that the stem length and the leaf area increase proportionally with the degree of salinity after spraying kinetin. Concerning the physiological properties, the application of this hormone in plants under stress induced a proportional increase in chlorophyll (a) and (b) with the concentration of used salt. Similarly, an increase of proline content is observed in the plants treated or not treated by kinetin.Keywords: Salinity- Triticum durum var KEBIR- Phytohormones- Kinetin- Foliar spray

Low angle normal faults in Internal rif (Morocco) and their bearing Implication on crustal thinning of the Alboran Domain

Several low angle, shallow dippinng normal faults are described from the internal domaine of the Rif chain. They dip gently towards the Alboran sea and cause important omissions in the stratigraphictectonic pile. These extensionai faults cut through the Ghomaride and Sebtides units and allow explaining the occurrence of flysch klippes overlying the Ghom arides nappes. The age of this extensionai event corresponds to that of the SerravaHan rifting stage of the Alboran seaPlusieurs failles normales à faible pendage inclinées vers la mer d'Alboran sont mises en évidence dans le Rif interne. L'extension associée à ces failles a produit des omissions importantes de terrains et a impliqué dans le déplacement des terrains appartenant au Domaine interne rifain ainsi que des terrains plus externes. Les lambeaux de nappes des flyschs superposés au Domaine interne rifain sont interprétés comme le résultat de ces déplacements extensifs. L'âge de cette extension coïncide avec le stade de rifting du Miocène moyen observé dans ia mer d'Albora