Journée des doctorants Géosciences Montpellier-10 …...Journée Des Doctorants Géosciences...

Journée Des Doctorants Géosciences Montpellier – 10 juin 2014

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Planning de la Journée des Doctorants Géosciences Montpellier est un laboratoire reconnu mondialement dans les sciences de la

Terre. La dynamique de la planète est la problématique fondamentale du laboratoire et s’étudie

au travers des différentes enveloppes terrestres. Les chercheurs accueillent et encadrent une

trentaine de doctorants dans des disciplines diverses.

Venez découvrir les travaux de ces jeunes chercheurs en apprentissage.

Attention : Les oraux auront lieu dans l’amphithéâtre du bâtiment 23.01. Nous vous invitons à

venir manger entre 12h et 14h, autour d’un buffet et de posters qui permettront des échanges

scientifiques dans un cadre convivial (au niveau du “fer à cheval »).

Cette journée a été organisée, avec le soutien du laboratoire Géosciences Montpellier,

par : Romain Le Roux Mallouf, Céline Baudouin, Manon Dubois, René Chamboredon,

et l’ensemble des Masters 1 et 2 pour les collations.

Buffet 12h-14h

: posters

Présentations

orales


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Sommaire des résumés:

Présentations ................................................................................................. 6

V. Baptiste: Deformation, hydration, and anisotropy of the lithospheric mantle beneath an active rift: constraints from mantle xenoliths from the North Tanzanian Divergence ......... 7

Y. Caniven: Dynamics of a strike-slip fault analog model: Effects of the tectonic loading rate. . 9

Tectonics of the Western Betics: the role of E-W strike-slip fault corridors ........................... 111

M. Genti: L’érosion nouvelle hypothèse pour l’origine des séismes en France. (Vulgarisation scientifique) ....................................................................................................................... 133

D. Laurent: Mécanisme de valve sismique associé aux circulations de fluides de bassin : exemple du Bassin Permien de Lodève (Hérault, France). ................................................ 155

R. Lehu: First estimate of M>6.5 earthquakes records in marine sedimentary archives off East Taiwan during the last 2,000 years .................................................................................... 177

M. Lejri: Stress inversion assumptions review .......................................................................... 19

A. Moy: Contribution à la modélisation physique du dosage des actinides par microanalyse électronique. ...................................................................................................................... 211

A. Poujol: Morphotectonics evidence of the 1755 historical earthquake of ........... Fez-Meknes, Morocco. .............................................................................................................................. 23

Posters ....................................................................................................... 266

V. Baptiste: Petrophysical constraints on the seismic properties of the Kaapvaal craton mantle root ..................................................................................................................................... 277

C. Baudouin Alkaline magmas in early stage rifting - volatile-rich nephelinites from East African Rift, north Tanzania, Manyara basin. .................................................................... 288

L. Campmas Typhoons driven morphodynamics of the Wan-Tzu-Liao sand barrier (Taïwan) . 30

R. Chailan: A new method for assessing spatial return levels of extreme waves ..................... 31

R. Chamboredon: Fluid inclusions and volatile-rich minerals in nephelinite as tracers of fluids beneath the NW African Craton (Saghro volcanic field, Anti-Atlas, Morocco) ................. 333

C. Denis: Water content and hydrogen behavior during metasomatism in the uppermost mantle beneath Ray Pic volcano (Massif Central, France) ................................................ 344

H. El Messbahi: Regional variability of lithospheric mantle beneath the Middle Atlas. ......... 355

L. Fernandez: Positioning the peridotite massifs of north-eastern Algeria in the geodynamic

evolution of the Western Mediterranean: A geochemical and geochronological study 377

B. Fores: Surveillance et modélisation du stockage de l'eau en zone karstique (Larzac, France) avec un gravimètre supraconducteur. .................................................................................. 39

M. Genti: Could Erosion in the Western Alps triggers large earthquakes in the Ligurian basin?............................................................................................................................................ 411

F. Gjetvaj: Non – fickian solute transport in heterogeneous medium .................................... 433


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R. Le Roux-Mallouf: Déformation Holocène de l’Himalaya du Bhoutan, apport de la géomorphologie et de la paléosismologie ......................................................................... 455

A. Marechal: Present-day strain partitioning and strain transfer across the Fairweather and Denali Faults in SW Yukon – SE Alaska .............................................................................. 477

HN. Nguyen : Déformations extrêmement lentes et mouvement verticaux : apport du GPS et du nivellement pour contraindre des modèles numériques ............................................... 49

N. Rasendra: Imagerie de l’anisotropie sismique de la croûte – Exemple de la faille de Denali : localisation de la déformation en profondeur à l’échelle lithosphérique. ........................ 511

F. Rétif : Realistic simulation of instantaneous nearshore water levels during typhoons ..... 533


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Présentations


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Deformation, hydration, and anisotropy of the lithospheric mantle

beneath an active rift: constraints from mantle xenoliths from the

North Tanzanian Divergence

Virginie BAPTISTE1, [email protected]

Alain Vauchez1, Andréa Tommasi1, Sylvie Demouchy1, Roberta Rudnick2 1 Géosciences Montpellier, Université Montpellier 2 & CNRS, CC 60, Place E. Bataillon, 34095 Montpellier cedex

5, France 2 Department of Geology, University of Maryland, College Park, Maryland 20742, USA.

Keywords: Rift, Peridotite, Deformation, Olivine CPO, Water contents, Anisotropy

We have analyzed the microstructures, the crystal preferred orientations (CPO), and calculated

the seismic properties of 53 mantle xenoliths from four localities within the East African rift

(North Tanzania Divergence), two within the rift axis, and two within the transverse volcanic

belt. OH concentrations in olivine were measured in 15 of these xenoliths.

Most samples have harzburgitic to dunitic compositions, and high olivine Mg#, suggesting

early, extensive partial melting. Within the rift axis, peridotites display mylonitic to

porphyroclastic microstructures, which record deformation by dislocation creep under high

stress, followed by variable, yet weak degrees of annealing. Highly sheared orthopyroxene

crystals in mylonite indicate that the deformation was initiated under high stress and probably

low temperature. However, reactions of replacement of orthopyroxene by olivine observed in

most samples suggest syn-kinematic, near solidus melt-rock reactions. Ubiquituous exsolutions

in orthopyroxene suggest significant cooling between this melt-assisted deformation and

xenolith extraction. Late metasomatism is evidenced by the occurrence of veins crosscutting the

microstructure, as well as the presence of pervasive interstitial clinopyroxene and phlogopite.

Axial-[100] olivine CPO predominates, suggesting the activation of the high temperature, low

pressure [100] (0kl) slip system, coherent with a transtensional deformation. Within the

transverse volcanic belt, Lashaine peridotites display very coarse-granular textures, indicating

deformation by dislocation creep under low deviatoric stress conditions followed by annealing.

The orthorhombic to axial-[010] olivine CPOs are consistent with the simultaneous activation of

[100](010) and [001] (010) slip systems, coherent with a transpressional deformation. Finally,

intermediate microstructures and CPOs are observed in Olmani may indicate a heterogeneous

deformation within the volcanic transverse belt. No systematic variations of olivine OH

concentrations between in axis and off-axis samples are observed. They vary between 2 and 12

ppm wt. H2O, however, the lowest concentrations are measured in mylonites. Maximum P

wave azimuthal anisotropy (AVp) ranges between 3.3 and 18.4% and the maximum S wave

polarization anisotropy (AVs), between 2.3 and 13.2%. The change in olivine CPO symmetry,

from dominantly axial-[100] peridotites from the rift-axis to orthorhombic in xenoliths from

Olmani and axial-[010] in peridotites from Lashaine, results in a variation in the seismic

anisotropy patterns. Comparison between olivine CPOs and SKS fast polarization directions is

consistent with a rift formed by a transtensional deformation.


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Legend: Map showing the North Tanzania Divergence and the location of the xenolith

localities.


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Dynamics of a strike-slip fault analog model: Effects of the tectonic

loading rate.

Yannick CANIVEN1, [email protected]

Stéphane Dominguez1, Roger Soliva1, Rodolphe Cattin1, Michel Peyret1, Jean Chéry1 and Christian Romano1 1Université Montpellier II, Lab. Géosciences Montpellier, UMR 5243, Place E. Bataillon, 34095 Montpellier

cedex, France

Keywords: seismic cycles, earthquakes, fault, analog modeling

The average seismic cycle duration extends from hundred to a few thousands years but geodetic

measurements and seismological data extend over less than one century. This short time

observation scale renders difficult to constrain the role of key parameters such as fault friction

and geometry, crust rheology, stress and strain rate that control the kinematics and mechanics of

active faults.

To solve this time scale issue, we have developed a new experimental set-up that reproduces

scaled micro-earthquakes and several hundreds of seismic cycles along a strike-slip fault. The

model is constituted by two polyurethane foam plates laterally in contact, lying on a basal

silicone layer, which simulate the mechanical behaviour of an elastoplastic upper crust over a

ductile lower crust, respectively. To simulate the boundary conditions of a strike-slip fault, a

computerized motoreductor system moves the two compartments on an opposite sens at a

constant low velocity (a few µm/s). The model scaling, deduces from analog material physical

parameters, implies that 1 cm in the model represents 2-3 km in the nature and 1 s is equivalent

to 5-15 years.

Surface-horizontal strain field is quantified by sub-pixel correlation of digital camera pictures

recorded every 16 µm of displacement. We record about 2000 horizontal-velocity field

measurements for each experiment. The analysis of model-interseismic and coseismic surface

displacements and their comparison to seismogenic natural faults demonstrate that our analog

model reproduces correctly both near and far-field surface strains. To compare the experiments,

we have developed several algorithms that allow studying the main spatial and temporal

evolution of the physical parameters and surface deformation processes that characterise the

seismic cycle (magnitudes, stress, strain, friction coefficients, interseismic locking depth,

recurrence time, ...). We also performed surface-velocity field inversions to assess the spatial

distribution of slip and stress at depth along the fault plane.

Our results suggest that far-field boundary-velocity conditions play a key role on the seismic

cycle by influencing rupture sizes, recurrence time and fault behaviour. We observed that low

loading rate generates rare large size characteristic earthquakes and high loading rate numerous

low to moderate magnitude more distributed earthquakes. Our first hypothesis is that this

behaviour may be controlled by the brittle/ductile coupling at the base of foam plates. For a high

strain rate, viscous forces in the silicone layer increase as well as coupling at the base of the

foam plates. These features force the fault to slip at a velocity close to the far field velocity and

induce a more heterogeneous stress field along the fault incompatible with characteristic

earthquake behaviour. For a low strain rate, silicone almost behaves as a newtonian fluid and

viscous forces strongly decrease, allowing the fault to locked and to accumulate more elastic

strain. Stresses are then relaxed by larger seismic events. Another hypothesis is that a part of

this behaviour may be also controlled by a time-dependent static frictional strength.


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Figure 1: a) Experimental set-up used to study the seismic cycle on a strike-slip fault ; b) Example of microquake with

horizontal velocity field (top) and displacement amplitude field (down).

Figure 2 : a) Historical seismicity (top) and corresponding cumulated coseismic offsets (down) for high loading rate (left)

and low loading rate (right).

Characteristics event

Main characteristics events

More Homogeneous slip distribution


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Tectonics of the Western Betics: the role of E-W strike-slip fault corridors

Gianluca Frasca1, [email protected]

Frédéric Gueydan2, Jean-Pierre Brun1

1 Géosciences Rennes, UMR 6118, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France, 2 Géosciences Montpellier, UMR 5243, Université Montpellier 2, place E. Bataillon, 34095 Montpellier Cedex 5,

France

Keywords: Gibraltar arc, back-arc tectonics, strike-slip faulting.

The arcuate Betic-Rif orogenic belt surrounds the Alboran Sea at the western tip of the

Mediterranean Sea. The tectonic origin of the Betic-Rif chain remains strongly debated.

Here, we investigate the tectonic units cropping out in the Western Betics (Malaga region,

Southern Spain) with the main goal of reconstructing the Oligo-Miocene evolution of the area.

New structural data and geological mapping together with available data allow us to

identify the main structural features of the area. Deformation is found to be extremely diffused

but two E-W elongated tectonic blocks with different lithological composition are outlined by

marked E-W dextral strike-slip corridors ending up in horse-tail splays.

The E-W strike slip corridors are responsible for Miocence tectonics of both the internal and

external zones in the Betic Cordillera.


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L’érosion nouvelle hypothèse pour l’origine des séismes en France.

(Vulgarisation scientifique)

Manon GENTI1, [email protected]

Jean Chery1, Philippe Vernant1, Rodolphe Cattin1

1 Géosciences Montpellier, CNRS-UM2, Place E. Bataillon, 34095 Montpellier, France

Mots clés : tremblements de terre, érosion

Vulgariser permet de prendre du recul sur ses recherches, et peut de nouvelles idées à

approfondir. Pour ma participation au concours « Ma Thèse en 180 secondes », j’ai pris plaisir à

vulgariser une partie de ma thèse.

Le titre officiel de ma thèse pourra ressembler à : Modélisation numérique de l’influence des

processus de surface sur la déformation de la lithosphère en domaine intraplaque. Pour

vulgariser tout ça j’ai du faire appel à l’imaginaire socio-discursif. La sismicité est un témoin de

la déformation, c’est pourquoi j’ai choisi de toucher le public en m’attaquant aux tremblements

de terre en France.

La France peut être considérée comme un domaine intraplaque, au vu des mouvements

horizontaux données par le GPS. Donc a priori il n’existe pas de forces qui s’opposent ! Cette

observation pose la question de l’origine des séismes en France. Quelles sont les forces qui

s’accumulent sur la faille ?

La localisation des séismes laisse penser qu’il existe un lien entre les montagnes et les séismes.

Deux points supplémentaires sont à retenir : le GPS montre un soulèvement dans les Alpes, et

des indices d’extension sont observés dans les Alpes et les Pyrénées.

Notre équipe de recherche a montré et propose que l’érosion soit le moteur du phénomène qui

permet ces observations. La métaphore utilisée pour expliquer le réajustement isostatique :

l’enlèvement une à une d’une pile de piècettes sur un flotteur dans un verre d’eau.

Avec cette nouvelle hypothèse testée par modélisation numérique 3D, j’espère que dans un an je

ferais trembler le monde de la géologie !

mailto:[email protected]


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Figure 1 Des forces aux extrémités des blocs font accumuler des contraintes à une faille bloquée. Lorsque la faille ne

résiste plus à ces forces, elle glisse ce qui produit des ondes sismiques et qu'alors la terre tremble!

Figure 2 La flexure vers le haut du trait vert est due au réajustement qu'induit l'érosion. La longueur finale du trait vert

est plus importante que le trait initial (noir pointillé). L’érosion peut être le moteur de l'extension et du soulèvement

observés dans les Alpes.


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Mécanisme de valve sismique associé aux circulations de fluides de bassin :

exemple du Bassin Permien de Lodève (Hérault, France).

D. Laurent1, M. Lopez1, A. Chauvet1, M. Thomas2, F. Chevalier2, P. Imbert3, S. Sizaret4, A-C.

Sauvage5, M. Buatier6, A. Gay1 1Géosciences Montpellier (France) ; 2 TOTAL E&P, Stavanger (Norway) ; 3 TOTAL SA, Pau (France) ; 4 Institut

des Sciences de la Terre d’Orléans (France) ; 5 EGIDE Environnement, Le Horps (France), 6 Laboratoire Chrono-

Environnement, Besançon (France).

Mots clés : fluide, texture, contrôle structural, faille-valve, inclusion fluide, 87Sr/86Sr

Au cours de l’enfouissement des bassins sédimentaires, les fluides interstitiels

initialement piégés au sein de la pile sédimentaire demeurent très mobiles et vont pouvoir

interagir entre eux et avec l’encaissant pendant plusieurs millions d’années. Dans ce contexte,

les zones de failles représentent des drains majeurs qui peuvent être empruntés et réactivés

périodiquement par ces fluides profonds dans des conditions de surpression créant ainsi une

cyclicité des ruptures. Ce mécanisme, dit de « faille-valve », a été principalement décrit dans le

domaine profond (>7km), à la limite avec le domaine métamorphique, mais très peu à l’échelle

d’un bassin sédimentaire.

Le demi-graben Permien de Lodève (Hérault, France), aujourd’hui exhumé, offre des

conditions d’affleurement exceptionnelles permettant d’accéder à des systèmes minéralisés

polymétalliques piégés au sein de failles normales de roll-over affectant les carbonates karstifiés

du Cambrien. Notre approche combine l’étude multi-échelle tectonique/texturale, des inclusions

fluides et géochimiques des corps minéralisés, avec pour principal objectif de décrypter

précisément le modèle mécanique de valve sismique dans la croûte supérieure.

Le remplissage essentiellement barytique se développe de manière cyclique soit dans les failles

ou dans des zones de décollement plus ou moins horizontales parallèles aux plans de

stratification, voire dans des paléokarsts. Trois types de remplissage sont identifiés. L’étude

microthermométrique des inclusions fluides démontre l’existence de fluctuations de pression

fluide dans le domaine supra-hydrostatique et des connexions avec le domaine superficiel au

cours des différents épisodes de minéralisations. Enfin, l’analyse isotopique du strontium ainsi

que les teneurs en éléments traces/terres rares confirment l’origine crustale des fluides à

l’origine des minéralisations ainsi que l’ouverture syntaxiale des zones de faille lors des

précipitations successives.

Cette étude démontre une histoire polyphasée des circulations de fluides dans la zone de

roll-over du Bassin de Lodève : (i) un premier événement lié à l’activation des failles lors du

rifting permien, avec cimentation d’une brèche d’implosion par le fluide qui va réduire la

cohésion du plan de cisaillement, (ii) des réactivations périodiques des plans de failles et

initiation de cisaillement aux interfaces stratigraphiques par la montée en pression de ces mêmes

fluides profonds et (iii) un dernier évènement tectonique syn-rift associé au piégeage des

derniers fluides de bassin et aux hydrocarbures.

Ce travail permet de préciser les conditions de piégeage des fluides ainsi que leur impact

au sein des zones de failles au cours de l’enfouissement des bassins sédimentaires. En

particulier, une dichotomie est mise en évidence entre le contrôle purement tectonique des

migrations de fluides et la réactivation cyclique de plan de cisaillement dans les failles et

parallèlement à la stratification sous la seule action des surpressions de fluide.


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Figure 3 : approche intégrée de caractérisation du mécanisme de valve sismique régissant le piégeage des fluides de

bassin.


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First estimate of M>6.5 earthquakes records in marine sedimentary

archives off East Taiwan during the last 2,000 years

Remi Lehu1, 2, [email protected]

Serge Lallemand1,3, Shu-Kun Hsu2,3, Laurent Dezileau1,3, Nathalie Babonneau3,4, Gueorgui

Ratzov5, Andrew T. Lin2,3

1 Geosciences Montpellier, University Montpellier II, France 2 Department of Earth Sciences, National Central University, Taiwan. 3 LIA,ADEPT, Taiwan-France. 4 Domaines Oceaniques, IUEM, Brest, France 5 IFREMER, Geosciences Marines-LES, Plouzané, France

Keywords: Subduction zone-offshore eastern Taiwan-turbidite-historical earthquakes

Large earthquakes are one of the main driving mechanisms for turbidity current generation

along active margins. When the turbidite sequences as well as the trigger mechanisms are well

defined among the sedimentary archives, it is possible to use turbidites records as a proxy for

paleoseismicity investigation. The Taiwan area, where the Philippine Sea Plate collides with the

Eurasian plate at a convergence rate of 80mm/yr, is one of the most seismically active areas in

the world and has been consequently struck repeatedly by destructive earthquakes. To better

constrain the recurrence intervals of large earthquakes, we have conducted two cruises in 2012

and 2013 during which piston cores (up to 4m long) and box-cores were retrieved in tectonically

controlled basin. We aimed at deciphering turbidite units and hemipelagic sequences with

special attention to the source of the turbidites such as river discharges or slope sediments

destabilized by earthquakes. From these cores we analyzed each event using several physical,

chemical and sedimentological proxies. Moreover fine details of vertical elemental distribution

acquired by X-ray fluorescence (XRF) scanning allow us to accurately identify and characterize

turbidite events. Analyzing two cores in the Ryukyu forearc, we have identified 23 beds that

differ from pelagic sediments and interpreted as resulting from slope instabilities. In the Luzon

volcanic arc area, two cores were used to identify 25 layers. 14C dating performed on planktonic

foraminifera and 210Pb-137Cs datings, provide a 2,000-years-long chronology of seismic events.

Precise dating, of the three most recent sedimentary layers of one box-core (36cm long), based

on 210Pb-137Cs and 137Cs chronology provides ages of 2002 ± 3 AD, 1953 ± 4 AD and 1936 ± 8

AD. These ages correspond to large instrumental earthquakes that occurred at a distance less

than 50 km from our sampling site: the 2003 Taitung Earthquake (Mw 6.8), the 1951

Chenggong Earthquake (Mw 7.1) and the 1935 Lutao Earthquake (Mw 7.0). Such a good

correlation between turbidites and (Mw> 6) historical instrumental seismic events suggests that

the record of mass transport deposits can be used as a paleoseismic indicator in this region.



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Figure1. Geodynamic context of Taiwan and historical seismicity over the 20th century. Green circles represent M>6.5

earthquakes and green reverse triangles show core sites. DF: Deformation Front, LVF: Longitudinal Valley Fault.


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Stress inversion assumptions review

Mostfa Lejri1,2 , [email protected]

Frantz Maerten1 , [email protected]

Laurent Maerten1 , [email protected]

Roger Soliva2 , [email protected]

1Schlumberger – MpTC, Parc Euromédecine, 340 rue Louis Pasteur, 34790 Grabels, France 2Géosciences Montpellier, Université Montpellier 2, Place E. Bataillon, 34095 Montpellier cedex 5, France

Wallace (1951) and Bott (1959) were the first to introduce the idea that the slip on each

fault surface has the same direction and sense as the maximum shear stress resolved on that

surface. This hypothesis are based on the assumptions that (i) faults are planar, (ii) blocks are

rigid, (iii) neither stress perturbations nor block rotations along fault surfaces occur and (iv), the

applied stress state is uniform. However, this simplified hypothesis is questionable since

complex fault geometries, heterogeneous fault slip directions, evidences of stress perturbations

in microstructures and block rotations along fault surfaces were reported in the literature. Earlier

numerical geomechanical models confirmed that the striation lines (slip vectors) are not

necessarily parallel to the maximum shear stress vector but is consistent with local stress

perturbations. This leads us to ask as to what extent the Wallace and Bott simplifications are

reliable as a basis hypothesis for stress inversion. In this presentation, a geomechanical multi-

parametric study using 3D boundary element method (BEM), covering (i) fault geometries such

as intersected faults or corrugated fault surfaces, (ii) the full range of Andersonian state of

stress, (iii) fault friction, (iv) half space effect and (v), rock properties, is performed in order to

understand the effect of each parameter on the angular misfit between geomechanical slip

vectors and the resolved shear stresses. It is shown that significant angular misfits can be found

under specific configurations and therefore we conclude that stress inversions based on the

Wallace-Bott hypothesis might sometime give results that should be interpreted with

care. Major observations are that (i) applying optimum tectonic stress conditions on complex

fault geometries can increase the angular misfit, (ii) elastic material properties, combined to

half-space effect, can enhance this effect, and (iii) an increase of the sliding friction leads to a

reduction of this misfit.






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Contribution à la modélisation physique du dosage des actinides par

microanalyse électronique.

Aurélien MOY1,2, [email protected]

Claude Merlet1, Olivier Dugne2 1GM, CNRS, Université de Montpellier II, Place E. Bataillon, 34095 Montpellier, France. 2CEA, DEN, DTEC, SGCS, LMAC, 30207 Bagnols-sur-Cèze, France.

Mots clés : Microanalyse – Actinides – Sans standard – Section-efficace

L’analyse par microsonde électronique (EPMA) est utilisée afin de quantifier, avec une grande

précision, les concentrations chimiques, à l’échelle micrométrique, d’échantillon solide. Elle

permet, par exemple, de quantifier les actinides présents dans les combustibles nucléaires neufs

ou irradiés, d’aider à la gestion des déchets nucléaires ou encore de dater certaines roches.

Malheureusement, ces analyses quantitatives ne sont pas toujours réalisables dû à

l’indisponibilité d’étalons de référence pour certains actinides. Afin de pallier cette difficulté,

une méthode d’analyse dite « sans standard » peut-être employée au moyen d’étalons virtuels.

Ces derniers sont obtenus à partir de formules empiriques ou à partir de calculs basés sur des

modèles théoriques. Toutefois, ces calculs requièrent la connaissance de paramètres physiques

généralement mal connus, comme c’est le cas pour les section-efficaces de production de rayons

X.

Au cours de ce travail, les section-efficaces de production des raies L et M du plomb [1], du

thorium et de l’uranium [2] ont été mesurées par impacts d’électrons sur des cibles minces

autosupportées (d’épaisseur variant de 0,2 à 8 nm) [3]. Les résultats expérimentaux ont été

comparés avec les prédictions théoriques de section-efficaces d’ionisation calculées par Bote et

al. [4] grâce à l’approximation de Born en ondes distordues (DWBA) et avec les prédictions de

formules analytiques utilisées dans les applications pratiques. Les section-efficaces d’ionisation

ont été converties en section-efficaces de productions de rayons X grâce aux paramètres

atomiques extraits de l’ « Evaluated Atomic Data Library » (EADL). Les résultats théoriques du

modèle DWBA sont en excellents accords avec les résultats expérimentaux (Figure a). Ceci

permet de confirmer les prédictions de ce modèle et de valider son utilisation pour le calcul de

standards virtuels. Les prédictions de ce modèle ont été intégrées dans le code Monte Carlo

PENELOPE [5] afin de calculer l’intensité de rayons X produite par des standards pur

d’éléments lourds (Figure b). Les calculs ont été réalisés pour les éléments dont le numéro

atomique est 89 ≤ Z ≤ 99 et pour des tensions d’accélération variant du seuil d’ionisation jusque

40 kV, par pas de 0,5 kV. Pour une utilisation pratique, les intensités calculées pour les raies L

et M les plus intenses ont été regroupées dans une base de données en fonction de la tension

d’accélération.

Les prédictions des standards virtuels ainsi obtenus ont été comparées avec des mesures

effectuées sur des échantillons de composition connue (UO2, ThO2, ThF4, PuO2…) et avec les

données acquises lors de précédentes campagnes de mesures. Le dosage des actinides à l’aide de

ces standards virtuels a montré un bon accord avec les résultats attendus. Ceci confirme la

fiabilité des standards virtuels développés et démontre que la quantification des actinides par

microsonde électronique est réalisable sans standards d’actinides et avec un bon niveau de

confiance.


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Légende : a) Résultats expérimentaux et théoriques de la section-efficace de productions des

raies M de l’uranium. b) Spectre calculé et mesuré de la raie U Mα pour un faisceau d’électrons

de 15 kV.


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Morphotectonics evidence of the 1755 historical earthquake of

Fez-Meknes, Morocco.

Antoine POUJOL1, [email protected]

Jean-Francois RITZ1, Philippe VERNANT1, Soufian MAATE2, and Abdelilah TAHAYT2

1Université MONTPELLIER 2, GEOSCIENCES, EARTH SCIENCE, MONTPELLIER, France 2CNRST, Institut National de Géophysique, Rabat, Morocco

Mots clés: South Rif Front, Fez (Morocco), Morphotectonics, Radiocarbon, "1755" Earthquake

The Southern Rif Front (SRF) is located at the southernmost frontal part of the Rif

Cordillera (Morocco) and overthrusts the foreland basins of Saiss and Gharb. Extending over a

length of ~150km between Fez, Meknes and Rabat cities, the SRF stands out as a major active

structure. It represents an important seismic hazard for these highly-populated cities as

evidenced by their historical seismicity records. The last larger historical earthquake in the area

occurred on the 27 November 1755 (almost a month after the large “Lisbon” earthquake of the

1st November 1755), striking the region of Meknes and Fez and causing many casualties. Its

intensity is reported to be VIII on the MSK scale. Using satellite imagery, aerial photographs

and field investigations, we carried out a morphotectonics study between Fez and Meknes to

identify the most recent traces of tectonic activity. Few kilometres westwards Fez city, we

identified evidence for a very recent reverse fault scarp at the foothills of the Jebel Thrat massif.

High resolution Digital Elevation Model of the fault scarp allowed determining a coseismic

vertical displacement of ~0.75-1m, which yields a reverse slip along the fault of 1.8-2.5 m for a

dip estimated at ~24° towards the North. According to Wells and Coppersmith’s regressive laws

(1994), this amount of displacement yields a Moment Magnitude comprised between 6.5 and 7,

which would correspond to a surface thrust rupture length of ~20-40 km. 14C dating of the

affected stream terrace yields an age of 1700±20 cal AD. These results suggest that the observed

features correspond to the 27 November 1755 historical earthquake. Cumulative deformations

are also observed within the studied area with uplifted, tilted and folded fluvial deposits. In

order to estimate the Holocene long term slip rate along the fault, we mapped an alluvial terrace

showing a 12 m vertical offset, and we sampled its sandy deposits for Optical Stimulated

Luminescence dating.


24

Field picture of the active South Rif Front (view from the SE - Fez city)

Long-term deformation: folding surface and tilted pebble bed

Recent deformation: "1755AD" historical earthquake thrust scarp


25


26

Posters


27

Petrophysical constraints on the seismic properties of the Kaapvaal craton

mantle root

Virginie BAPTISTE1, [email protected]

Andréa Tommasi1

1 Géosciences Montpellier, Université Montpellier 2 & CNRS, CC 60, Place E. Bataillon, 34095 Montpellier

Keywords: Peridotite, Craton, Kaapvaal, Anisotropy, Seismic properties

We calculated the seismic properties of 47 mantle xenoliths from 9 kimberlitic pipes in

the Kaapvaal craton based on their modal composition, the crystal preferred orientations (CPO)

of olivine, ortho- and clinopyroxene, and garnet, the Fe content of olivine, and the pressures and

temperatures at which the rocks were equilibrated. These data allow constraining the variation

of seismic anisotropy and velocities within the cratonic mantle. The fastest P and S2 waves

propagation direction and the polarization of fast split shear wave (S1) are always subparallel to

olivine [100] axes maximum concentration, which marks the lineation (fossil flow direction).

Seismic anisotropy is higher for high olivine contents and stronger CPO. Maximum P-wave

azimuthal anisotropy (AVp) ranges between 2.5 and 10.2% and the maximum S-wave

polarization anisotropy (AVs), between 2.7 and 8%. Changes in olivine CPO symmetry result in

minor variations in the seismic anisotropy patterns, mainly in the apparent isotropy directions

for shear wave splitting. Seismic properties averaged over 20 km thick depth sections are,

therefore, very homogeneous. Based on these data, we predict the anisotropy that would be

measured by SKS, Rayleigh (SV) and Love (SH) waves for 5 end-member orientations of the

foliation and lineation. Comparison to seismic anisotropy data in the Kaapvaal shows that the

coherent fast directions, but low delay times imaged by SKS studies and the low azimuthal

anisotropy with SH faster than SV measured using surface waves are best explained by a

homogeneously dipping (45°) foliations and lineations in the cratonic mantle lithosphere.

Laterally or vertically varying foliation and lineation orientations with a dominantly NW-SE

trend might also explain the low measured anisotropies, but this model should also result in

backazimuthal variability of the SKS splitting data, not reported in the seismological data. The

strong compositional heterogeneity of the Kaapvaal peridotite xenoliths results in up to 3%

variation in density and in up to 2.3% variation of Vp, Vs, and Vp/Vs ratio. Fe depletion by melt

extraction increases Vp and Vs, but decreases the Vp/Vs ratio and density. Orthopyroxene

enrichment due to metasomatism decreases the density and Vp, strongly reducing the Vp/Vs

ratio. Garnet enrichment, which was also attributed to metasomatism, increases the density, and

in a lesser extent Vp and the Vp/Vs ratio. Comparison of density and seismic velocity profiles

calculated using the xenoliths’ compositions and equilibration conditions to seismological data

in the Kaapvaal highlights that: (i) the thickness of the craton is underestimated in some seismic

studies and reaches at least 180 km, (ii) the deep sheared peridotites represent very local

modifications caused and oversampled by kimberlites, and (iii) seismological models probably

underestimate the compositional heterogeneity in the Kaapvaal mantle root, which occurs at a

scale much smaller than the one that may be sampled seismologically.


28

Alkaline magmas in early stage rifting - volatile-rich nephelinites from

East African Rift, north Tanzania, Manyara basin.

Céline BAUDOUIN1, [email protected]

Fleurice PARAT1

1UMR 5243 – Géosciences Montpellier, UM2 – 2 Place Eugène Bataillon 34095 Montpellier cedex 5

Keywords: Intracontinental Magmas, Early-stage Rifting, Volatiles elements

The narrow rift valley of the East African Rift expands over 200 km, forming the North

Tanzanian Divergence (NTD) and separates 2 geologically distinct areas. (1) In the north, the

Natron basin is characterized by intense magmatic and shallow seismic activity (<10 km). (2) In

the south, the Manyara-Balangida basin is characterized by a scarce volcanic activity: Kwaraha

and Hanang volcanoes, a small cone (Labait), several phreatic maars (Basotu), and deep

earthquake swarms (20-35 km) at the border of the Tanzanian craton. The main aim of my

thesis is to characterize the source and composition of the magmas and fluids present in the

south part of the NTD, and compare them to those within the northern area. This study is part of

a larger geophysical project constraining the percolation of volatile-rich liquids in the lower

crust to better assess the seismic activity.

Alkaline lavas from Kwaraha are mafic (Mg# = 57-66), alkali-poor (Na2O+K2O = 2-5.6 wt.%)

and Ca-rich (CaO > 13 wt.%) nephelinites and carbonatitic lavas (CaO = 62 wt.%). These

nephelinites have a paragenesis with olivine (Fo83-85), cpx (Mg# = 80-87), phlogopite (F = 0.5

wt%, BaO = 0.25 wt.%) and magnetite (Usp = 0.15-0.2). On the other side, Hanang nephelinites

are silica-poor (Mg# = 30-40) and alkali-rich (Na2O+K2O > 10 wt.%) and highly enriched in

incompatibles elements (Sr > 5000 ppm, Nb > 500 ppm). Hanang lavas have a paragenesis with:

nepheline, cpx (Mg# = 40-68), melanite (Ti-Ca Garnet), titanite and magnetite. Melt inclusions

in nepheline indicate volatile-rich silicate liquid with up to 1.2 wt.% F, 0.45 wt.% Cl and 1.8

wt.% SO3.

Two other volcanoes are present south of the NTD: Labait cone (10 km south to Hanang) and

Basotu craters (80 km west to Hanang) with different mineralogy and geochemistry. Labait

lavas are mafic and silica-undersaturated (Mg# = 79, SiO2 < 34.9 wt.%) with olivine (Mg# = 81-

87), titanite, magnetite (Usp = 0.1), F-apatite (0.05 wt% SO3) and Ni-sulfide (Ni = 5.7 wt.%),

whereas the Basotu craters represent a group of 30 aligned phreatic explosive craters, with

carbonatitic tuff ring (CaO = 41 wt.%).

The petrological and geochemical preliminary studies of lavas from the Manyara-Balangida

basin show strong differences compared to the NTD volcanoes. Lavas from the south part have

more silica-undersaturated and alkaline-rich trends. Moreover, nephelinites are characterized by

the presence of phlogopite phenocrysts (H2O-F-bearing mineral) and volatile-rich melt

inclusions (S, F, and Cl) in nepheline. Complementary analyses in melt inclusions (H2O, CO2,

trace elements) and in situ accessory minerals analyses will be performed to constrain the

composition of fluids and magmas in the Manyara-Balangida basin.


29

Typhoons driven morphodynamics of the Wan-Tzu-Liao sand barrier

(Taïwan)

Lucie CAMPMAS1,4 , [email protected]

Frédéric BOUCHETTE1,4, Samuel MEULE2,4, Jying-Yih LIOU3

1 Montpellier II university, Géosciences-Montpellier CNRS, UMR 5243, 34095 Montpellier, France 2 Aix-Marseille university, CNRS IRD CEREGE, UM34, 13545 Aix en Provence, France 3 National Cheng Kung University, No.1, University Road, Tainan City 701, Taïwan 4 GLADYS / SO LTC, OSU OREME, CNRS / Montpellier II university, France

Keywords: Morphodynamic patterns, Monsoon/typhoons seasons, Shoreline changes

METHODOGY

In the framework of the KUNSHEN project, 7 months of monitoring (2011-2012) provided 20

topobathymetric surveys (within a 350 m long segment of the barrier from a water depth of ~

1.5 m below the lowest tide level to the back-barrier) and acquisitions of nearshore

hydrodynamics including velocity profiling and free surface measurement. Morphologic

changes were monitored using D-GPS each week during winter monsoon season and just before

and after each event during summer typhoon season. Offshore waves were extracted at Cigu

buoy (1,5 km off the coast in 18 m of water depth). Additionally, nearshore waves and water

level on the beach were acquired from the current profiler deployed 400 m off the coast in 4 m

of water depth and a network of pressure sensors deployed along a cross-section through the

barrier, respectively.

MORPHOLOGICAL CHANGES DRIVEN BY TYPHOON, A GROUP OF TYPHOONS

AND THE WHOLE SEASON

Amongst the eight studied typhoons, TALIM is the most energetic and representative event

observed of the seasonal pattern. Offshore wave height reached H1/3 = 10,34 m (Tp = 14,6 s) at

Cigu buoy and Hs = 2,3 m (Tp = 13,4 s) at the profiler. At the storm apex, the dune-top (3 m

above mean sea level) has been surged. Morphological changes included 6,7 m of dunefoot

retreat and a sand transfer from a dune breach to wash-over deposits in the lagoon. More

surprisingly, the foreshore was nourished (+3387 m3, +0,077 m above mean sea level in

average) as well as the whole sand barrier (+2345 m3). This sand input is interpreted as the

ultimate stage of the landward migration cycle of subtidal sandbars occurring throughout the

whole season driven by groups of typhoons. Although winter are erosive season (-4146 m3), the

summer results in an accretion period (+3431 m3) with a foreshore nourishment (+5667 m3,

+0,25 m above msl) and a shoreline seaward shift (10,4 m) (figure 1). Over the annual time

period, the sand barrier recorded 18,5 m of retreat concomitantly with a 11,1 m widening

without any significant abrasion of the dune-top or sand loss.



30

Figure 1: a) Study area of Wan-Tzu-Liao sand barrier. b) Crosshore profile of the study area monitored from 2011-2012

with typology used. c) Wave and wind conditions from 2011 to 2012. Wave conditions are measured at Cigu buoy. Wind

conditions are measured at Cigu buoy until June 2012 and at the inland station from June to August 2012.


31

A new method for assessing spatial return levels of extreme waves

Romain Chailan1,2,3,4, [email protected]

Frédéric Bouchette1, Anne Laurent2, Gwladys Toulemonde3

1 Géosciences Montpellier – Université Montpellier 2 – 34095 Montpellier cedex 2 Lirmm – Université Montpellier 2 –34095 Montpellier cedex 3 I3M – Université Montpellier 2 –34095 Montpellier cedex 4 IBM France – Parc industriel de la Pompignane –34060 Montpellier cedex 2

Keywords: Extreme analysis, Max-stable processes, Wave-features hindcast

CONTEXT

In the analysis of coastal hazards, the features of extreme waves are determining information to

question the impact of storms to the coast. The spatial behaviour of extreme waves is even more

valuable especially since it is sparsely provided. Regarding recent applications in other contexts,

a kind of statistical models called max-stable processes is relevant for modelling spatial extreme

events. Max-stable processes are extensions of the well-known Generalized Extreme Value

(GEV) formalism. Unlike univariate approaches, max-stable processes consider spatial

dependence of a phenomenon. Such a modelling also overtakes a standard multivariate

approach by providing information continuously over the area studied, even where no

observation is available. Relying on such a stochastic modelling, the aim of this study is to

discuss the extreme waves hazard in the Gulf of Lions, focusing on their spatial behaviour.

METHOD

The storm-waves in the Gulf of Lions are well known for their abrupt changes. However, they

are only monitored i) by four surface buoys and ii) for a maximum period of a decade. We use

those data to perform a preliminary study on significant waves. Whether using univariate

(Fischer and Tippett, 1928) or bivariate (Resnick, 1987) modelling, a bias occurs while

extrapolating data from the stochastic model to obtain long return levels. The bias results from

the lack of long historical data set and hence the high sensitivity of the stochastic model

regarding the few extreme events recorded during that period. Regardless this drawback,

bivariate extreme value distributions on significant waves show a strong spatial dependence.

Thus we need to use a spatial approach as an alternative to fully integrate the dependence

between each observed site. One way is to use max-stable models (Smith, 1990; Schalther,

2002). Well-fitted max-stable models and therefore the quality of their extrapolations rely on the

availability of a representative data set, both in time and space. To pass over the scarcity of

observations, a strategy based on numerical simulation of the wave-features is much relevant

although it can introduce numerical approximations over the domain studied. Therefore we

build a wave hindcast for a fifty-one-year period (1961-2012) thanks to the third generation

wave model WaveWatchIII® in its most recent development (Tolman, 2014). Driven by

regional atmospheric and oceanic re-analyses, WaveWatchIII® performs a wave spectral

modelling on a refined unstructured grid. Several max-stable models are fitted to this reliable

data set. The best of those is selected to determine quantities of interest, showing that such a


32

combination of numerical wave modelling and stochastic modelling significantly enhances the

understanding of extreme waves behaviour (see simulation Figure 1).

Among these quantities, a mapping of extreme waves return levels is constructed. Joint

probabilities questioning -- e.g., the probability of having a significant-wave at both sites A and

B over their marginal 10-year return value -- are also introduced to demonstrate the benefits

from the use of spatial max-stable modelling against classical univariate approaches.

Legend: A simulated max-stable process (Schlather, 2002) of significant waves over the

Gulf of Lions. It is generated from a max-stable model, here fitted to academic data. Stars

are surface-buoy locations. The spatial extreme modelling formalism requires more sites and

long data time series to extrapolate such information. This is achieved through the 51-year

hindcast simulation.


33

Fluid inclusions and volatile-rich minerals in nephelinite as tracers of

fluids beneath the NW African Craton (Saghro volcanic field, Anti-

Atlas, Morocco)

René CHAMBOREDON1, [email protected]

Fleurice Parat1, Marie-Christine Boiron2

1 UMR5243 – Géosciences Montpellier, UM2 – Place E. Bataillon, 34095 Montpellier cedex 5, France 2 UMR7359 – GeoRessources Nancy, BP 20023, 54501 Vandœuvre les Nancy cedex, France

Keywords: Volatiles, fluid, liquid, mantle, alkaline lava, nephelinite, fluid inclusion, Raman,

microthermometry, olivine, metasomatism.

Volatile-bearing minerals in intraplate alkaline lavas attest of the presence of fluid

and/or volatile-rich liquid in the mantle. Fluid/liquid may be derived from asthenospheric

plumes, metasomatized subcontinental lithosphere or subducted material, and are therefore key

elements to understand magma genesis and mantle dynamics. To address the question of the

origin and composition of deep fluid and/or volatile-rich liquid, we investigated whole-rock and

mineral geochemistry and fluid inclusions of mafic alkaline lavas from the Saghro volcanic field

(Morocco, NW African Craton).

The mafic lavas are nephelinites with phenocrysts of olivine (Fo90–82), clinopyroxene

(Mg# = 87–49), nepheline and volatile-rich minerals: phlogopite, apatite (F = 1.0–2.9 wt.%, Cl

= 0.11–0.26 wt.%, SO2 = 0.06–0.42 wt.%), pyrrhotite (NFeS = 0.90–0.98) and magnetite (Xulvö

= 0.19–0.21). The mineral assemblage and composition constrain the pre-eruptive conditions of

nephelinite at oxidized redox state (logfO2=NNO–NNO+1) and 1000-1100°C (cpx-melt

equilibria). Nephelinites are mafic alkaline silica-undersaturated lavas (Na2O+K2O = 2.1–6.2

wt.%, SiO2 = 37–43 wt.%, Mg# = 70–62). Their high Ca/Al (1.0–1.5) and Zr/Hf (44.2–55.9)

ratios, high concentration in incompatible elements and negative anomalies in K, Zr, Hf and Ti

suggest a carbonatite-metasomatised peridotite source.

Primary fluid inclusions are present in olivine (Fo90–85) as (i) isolated or trails of

translucent fluid inclusions; (ii) dark isolated inclusions with daughter minerals of nepheline ±

apatite, and (iii) multi-phased inclusions with fluid and daughter minerals of nepheline ± apatite

± magnesite ± phlogopite. Microthermometry and micro-Raman spectrometry study of

translucent inclusions indicates pure supercritical CO2. Assuming a temperature of 1100°C, the

trapping pressure for pure CO2 system is in the range 300–1050 MPa.

Our study indicates that fluid and/or volatile-rich silicate liquid (C-O-H-S-Cl-F) is

involved during the genesis and evolution of alkaline magma. Fluid-rock interaction may have

been an important process beneath the NW African craton, leading to metasomatised mantle

with CO2–rich carbonatitic components.


34

Water content and hydrogen behavior during metasomatism in the

uppermost mantle beneath Ray Pic volcano (Massif Central, France)

Carole DENIS 1, [email protected]

Olivier ALARD1, Sylvie DEMOUCHY1 1 Geosciences Montpellier, University of Montpellier 2, place E. Bataillon, Montpellier, France

Keywords: Peridotite, water content, metasomatism, Massif Central

From experimental studies, we know that some of the Earth’s water can be stored as hydrogen

in point defects in the nominally anhydrous minerals (NAMs) of the Earth’s mantle. These

NAMs (e.g. olivine, pyroxenes and garnet) can contain up to hundreds of parts per million

hydrogen atoms. To assess this important deep water reservoir and the Earth deep water cycle,

water content must be quantified as well as the H behavior during mantle key processes such as

melting and metasomatism.

Nine xenoliths of spinel peridotite from the Ray Pic locality, in the southern part of the French

Massif Central (France) have been characterized by major, minor and trace elements

compositions including water contents were obtained by electron microprobe, laser ablation-

ICPMS and FTIR, respectively.

The sample suite investigated is lherzolites equilibrated at relatively low temperatures

(900 < T ≤ 1050ºC, using Ca-in pyroxenes, [1]). All samples show recrystallized

microstructures varying between porphyroclastic, coarse granular and equigranular. Bulk major

element compositions, modal abundances, mineral compositions and equilibrium temperatures

are typical of the cold-uppermost part of the ‘fertile’ mantle lithosphere beneath the Ray-Pic

area [2; 3]. However, contrary to previous studies, 6 xenoliths out of 9 show pargasite, with

modal abundances varying from 0.2 up to 8.2%.

Cpx’s normalized REE patterns show a continuum between light REE depleted ((La/Sm)N≈ 0.3)

to L-REE enriched patterns ((La/Sm)N≈16) and a relatively flat M-REE to H-REE segments

((Sm/Yb)N= 0.91±0.26). With suggest two types of metasomatism (1) with L-REE enriched

patterns show also U and Th enrichments but HFSE negative anomalies, usually ascribed to the

percolation of volatile-rich small volume melts within the cold sub-continental lithosphere [3; 4;

5]. And (2) a steady enrichment from light to heavy REE ascribed to a metasomatism at higher

melt/rock ratio.

H2O contents for the nominally anhydrous mineral (NAMs: ol, opx, cpx) are within the common

range of other spinel peridotites; with the highest hydrogen concentration in cpx and the lowest

in olivine. No correlation between hydrogen concentrations and (La/Sm)PM was observed.

Further, there is no correlation between H2O content in NAMs and the occurrence and/or

abundance of amphibole. However, broad correlations between water content in minerals and

(Yb)PM in clinopyroxene were found, suggesting that the variability of H2O content in NAMs is

primarily due to melt depletion. Implications for hydrogen behavior and water contents during

key mantle processes will be further discussed.



35

Regional variability of lithospheric mantle beneath the Middle Atlas.

Hicham EL MESSBAHI1, 2 , [email protected]

Jean-Louis Bodinier2, Alain Vauchez2, Jean-Marie Dautria2, Houssa Ouali1, and Carlos J.

Garrido3

1. Equipe Géomatériaux, Université Moulay Ismaïl, Faculté des Sciences, BP 11201, Zitoune, Meknès, Morocco

2. Géosciences Montpellier, Université de Montpellier 2, Cc 60, Place Eugène Bataillon, 34095 Montpellier

3. Instituto Andaluz de Ciencias de la Tierra (IACT), CSIC and UGR, Avenida de las Palmeras 4, 18100 Armilla,

Granada, Spain

The ‘tabular’ Middle Atlas, between Azrou and Timahdite, is an area where intra-plate

Cenozoic volcanism coincides with nearly 2000m uplifting of the undeformed Mesozoic cover

and the maximum of lithospheric thinning beneath continental Morocco. This region also

concentrates the principal mantle xenolith localities in Morocco. It is therefore a key area to

study the mechanisms of lithospheric thinning and constrain the component of mantle buoyancy

that is required to explain the Moroccan reliefs. Previous studies have focused on a single

locality - the Bou Ibalghatene maar, in the central part of the volcanic district. There, the mantle

xenoliths show extensive reactions with silicate and carbonate melts that led to the formation of

a range of lithologies characterized by substantial olivine, clinopyroxene or amphibole

enrichment, as well as incompatible trace element enrichment. However, a survey of mantle

xenoliths from nine localities distributed throughout the Azrou-Timahdite district indicates that

the reaction and metasomatic imprints are less pronounced or virtually absent in the other suites.

The Bou Ibalghatene suite could represent a restricted area of focused melt flow through the

lithosphere. The present study focuses on mantle xenoliths from the Tafraout maar, located

45km to the North-East of Bou Ibalghatene and distal to the main volcanic district. The maar is

situated on the NE-SW North Middle Atlas Fault, a major transpressive fault separating the

‘folded’ Middle Atlas, to the South-East, from the ‘tabular’ Middle Atlas, to the North-West.

The samples have been investigated for their mineralogy, microstructures, crystallographic

preferred orientation (EBSD-SEM), and bulk rock and mineral compositions (XRF, EPMA and

LA-ICP-MS). They differ from the Bou Ibalghatene mantle xenoliths by the presence of fine

grain samples (mylonites), the lack of hydrous metasomatic phases (amphibole and phlogopite),

somewhat lower equilibrium temperatures, a higher fertility degree, and less enriched trace

element compositions. Several samples show LREE-depleted clinopyroxene compositions that

have not been observed at Bou Ibalghatene. These results indicate significant variations of the

mechanisms and degree of lithosphere-asthenosphere interaction across the Azrou-Timahdite

plateau. The Tafraout xenoliths may represent distal and attenuated effects of a mantle

upwelling centered on the Bou Ibalghatene maar and bordered by the Middle Atlas Fault to the

South-East. The Tafraout suite also records incipient stages of the lithosphere-asthenosphere

interaction that were erased by subsequent melt/fluid processes beneathBou Ibalghatene.


36


37

Positioning the peridotite massifs of north-eastern Algeria in the

geodynamic evolution of the Western Mediterranean: A geochemical

and geochronological study

Laure Fernandez1, [email protected]

Bosch, D. 1, Bruguier, O. 1, Hammor D. 2 , Monié, P. 1, Arnaud, N. 1, Caby., R 1

1 Géosciences Montpellier, UMR-CNRS 5243, Université de Montpellier 2, Place Eugène Bataillon, 34095

Montpellier, Cedex 05, France 2Université Badji-Mokhtar, BP12, El-Hadjar, Annaba 23 000, Algeria

Keywords: Geodynamic, geochemistry, geoschronology, isotopy, Mediterranean area

The dismembered fragments of the Alpine belt recovered in various places around the

Mediteranean basin are witnesses of the collisional events between Africa and Eurasia and of

the opening of the western Mediterranean basins during the Cenozoic. In the eastern part of

North Algeria (figure 1), basic and ultrabasic rocks outcrop in the Edough massif, which belong

to the internal zone of the Magrebides. Preliminary works [Bosch & al., 2014] from this area

have proposed that both amphibolites from Kef Lakhal and metagabbros from Bou Maiza

correspond to components formed in a back-arc basin environment.

This study is focused on the petrology, geochemistry and geochronology of the mantle rocks

from Kef Lakhal (KL) and Sidi Mohamed (SM) areas in order to constrain their origin and age

and, thus to propose a suitable scenario for their evolution in time and space during the

Cenozoic. The peridotites show a wide range of Mg number, mainly between 82 and 89.6 with

lower values measured for the Kef Lakhal peridotites. The amphiboles from Kef Lakhal are

mostly magnesio-hornblende and pargasite. Garnets from amphibolites range from almandine to

grossular.

Amphibolites display MORB-type REE patterns evolving from slightly depleted to enriched

patterns (0.5<La/SmN<2, 0.6<La/Yb<3). Peridotites present flat CHUR-normalized REE

profiles with a marked negative Eu anomaly for KL samples. The Nd and Hf isotopes for both

amphibolites and peridotites can be separated into two distinct batches. A first group shows a

typical DMM signature for Nd and Hf isotopes with Sr isotopic ratios more or less modified by

seawater impact. A second group yields significantly lower Nd and Hf isotopic values (down to

0.512200 and 0.28207, respectively) combined with higher Sr isotopic ratios (up to 0.7147).

These values suggest participation of an enriched component similar to detrital sediments,

which is also supported by Pb isotopes.

The Ar-Ar and U-Pb ages (in progress) will help decipher the evolution of these different

components and appear as essential in order to replace the NE algerian massifs in the

geodynamical evolution of the western Mediterranean during the Cenozoic.


38

Figure 1: Geological map and localisation of Edough (Algeria), modified after Caby et al., 2001.

Bibliography

Bosch, D., Hammor, D., Mechati, M., Fernandez, L., Bruguier, O., Caby, R., & Verdoux, P.

(2014). Geochemical study (major, trace elements and Pb–Sr–Nd isotopes) of mantle material

obducted onto the North African margin (Edough Massif, North Eastern Algeria): Tethys

fragments or lost remnants of the Liguro–Provençal basin?. Tectonophysics.

Caby, R, D Hammor, and C Delor. “Metamorphic Evolution, Partial Melting and Miocene

Exhumation of Lower Crust in the Edough Metamorphic Core Complex, West Mediterranean

Orogen, Eastern Algeria.” Tectonophysics 342, no. 3–4 (December 2001): 239–273.

doi:10.1016/S0040-1951(01)00166-4.


39

Surveillance et modélisation du stockage de l'eau en zone karstique

(Larzac, France) avec un gravimètre supraconducteur.

Benjamin FORES1, [email protected]

Cédric Champollion1, Nicolas Le Moigne1, Jean Chéry1

1Géosciences Montpellier, UMR 5243, Université Montpellier II, France

Mots clés : Gravimétrie, Supraconducteur, Karst, Modélisation hydrologique

Réussir à quantifier le stockage et le transfert de l'eau souterraine en domaine karstique est

crucial pour la gestion et la protection des ressources en eau. Étant donné la très forte

hétérogénéité des propriétés hydrogéologiques des karsts, les observations géophysiques telles

que le suivi temporel de la gravité pourraient être utiles pour combler le vide entre les études à

l'échelle locale (basées sur des forages, capteurs d'humidité...) et l'échelle globale (chimie, débit

des rivières...).

Depuis plus de deux ans, l' igrav#002, un gravimètre supraconducteur de nouvelle génération,

mesure en continu dans l'observatoire ''GEK'' : Géodésie en Environnement Karstique, sur le

plateau du Larzac, dans le sud de la France. L'observatoire est situé sur plus de 250 m de

dolomite karstifiée, avec une zone non saturée d'environ 150 mètres. Dans cette étude, nous

présenterons d'abord une évaluation des données du gravimètre supraconducteur (calibration,

dérive, corrections). Ensuite, une analyse détaillée des effets globaux, des effets topographiques

et du bâtiment sera faite afin d'estimer le stock d'eau uniquement. Enfin, un premier modèle

hydrologique simple sera présenté pour débuter l'interprétation de l'hydrologie karstique de la

zone.



40

a)

b)

Légende : a) l'observatoire GEK sur le Larzac ; b) l'igrav dans la chambre centrale isolée du GEK ; c) comparaison

entre les données de l'igrav et les données hydrologiques classiques (pluviométrie / débit de la source)


41

Could Erosion in the Western Alps triggers large earthquakes in the

Ligurian basin?

Genti M. 1, [email protected]

Chéry J. 1, Vernant P. 1, Larroque C. 2

1 Géosciences Montpellier, CNRS-UM2, Place E. Bataillon, 34095 Montpellier, France 2 Géosciences Azur, UMR 6526 CNRS-UNS, 250 av. Einstein, 06560 Valbonne, France

Keywords: Ligurian basin, 2D thermo-mechanical modelling, erosion, seismicity, isostatic

rebound.

Earthquakes express present-day deformation at the Alps-Ligurian basin junction.

Convergence rates across the Western Alps are below the uncertainty threshold of the

continuous GPS measurements (< 0.3 mm/yr), but unexpectedly, the vertical rates derived

from the GPS are significant and up to 2 mm/yr. Furthermore, the range is underlined by

moderate but frequent instrumental seismicity. Focal mechanisms show extension in regions

of moderate to high elevations with a direction normal to the Western Alps range axis, while

their foreland is associated to strike slip and thrust faulting. How can be explained these very

high uplift rates and seismotectonic regime in an intraplate like kinematic deformation pattern

remains an open question.

Recent 2D finite element models have tried to answer to this question by showing that erosion

of mountain topography in low convergent zones induces a significant deformation of the

lithosphere. These models suggest two distinct seismotectonic zones characterized by

extension and uplift below the moderate to high topographic mountain range and shortening

in foreland. However, these models where not applied to a specific case study.

The last deadly earthquake was in 1887, in Ligurian Basin, with an estimated magnitude of

Mw=6,7. Many hypotheses are suggested to explain this active deformation. Using a 2D

cross-section of the Alpine-Ligurian margin, we study the effects of the processes surface

impact on the deformation pattern of the Ligurian Basin, and the possible triggering of

earthquake like the 1887 one.



42

Figure 4 Sedimentation rate influence the slip rate of a 75° north dipping plane fault (friction = 0.02) emerging at the

margin foot.

4.5 5 5.5 6 6.5 7 7.5

8

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

ero

sio

n

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

sedimentation


43

Non – fickian solute transport in heterogeneous medium

Filip GJETVAJ1 , [email protected]

Philippe Gouze1

1UM2, Géosciences Montpellier Place Eugène Bataillon, 34095 Montpellier, France

Keywords: Transport, Non-Fickian, Dispersion, Solute, Experiment

Solute transport managed by fluid flow in heterogeneous media has important role when

we want to ensure safe disposal of nuclear waste, access to clean drinking water or to have

control on any other process that includes contaminant transport in aquifers. Classical solute

transport theory developed in 1950s describes solute cloud spreading due to influence of

molecular diffusion and kinematic dispersion. Kinematic dispersion is a mixing phenomenon

that on a pore scale occur due to different path lengths, velocity profile in each pore and

velocity differences between pores. This processes are described by (Fickian) advection-

dispersion equation (ADE), but experiments both in situ and in laboratory shows that ADE

fails to predict true behavior of solute transport.

Breakthrough curves (BTCs) obtained by experiment are strongly asymmetrical with long

recovery times. Although concentration in late times has several orders of magnitude lower

value comparing to a peak concentration this tail cannot be neglected. Such behavior is result

of heterogeneities that exists even in most homogeneous structures. Even thought

theoretically if there is large enough homogeneous media, the transport will become Fickian

this is not realistic option for any real aquifer because heterogeneities exists on multiple scales

and they all affect solute transport.

In last twenty years due to technical development it has been recognized that matrix diffusion

is very important transport mechanism. Matrix diffusion is process where solute diffuses

between regions of flowing water and stagnant regions. This effect occur due to concentration

differences between two zones. Solute is transported by flow through mobile zone and

diffuses to stagnant zone. After the peak concentration has passed “clean” water enters mobile

zone and reverse process occur. Now concentration in stagnant zone is larger than in mobile

and solute diffuses back, this process is relatively slow comparing to advection because it is

dominated by diffusion with small concentration gradients. Tailing of BTCs is as well caused

by heterogeneities and it can be difficult to distinguish influences of these two processes.

It is necessary to develop tools that will allow to predict and quantify influence of matrix

diffusion and media heterogeneities to BTCs tailing. This can be achieved by performing

laboratory experiments on porous media with different properties (heterogeneities and

mobile/immobile zone ratio). 3D images of such pore space will give base to perform

numerical simulation of transport and determine coefficients. The same way of determination

coefficient will be used for other samples and results from numerical simulation will be

compared with experiment data in order to validate procedure.


44

Fig. 1 BTC showing tracer experiment with uranine (non reactive tracer), Fickian (ADE) and non-Fickian model

on same data set


45

Déformation Holocène de l’Himalaya du Bhoutan, apport de la

géomorphologie et de la paléosismologie

Romain LE ROUX-MALLOUF1, [email protected]

Rodolphe CATTIN1, Matthieu FERRY1, Jean-François RITZ1, Vincent GODARD2

1 Laboratoire Géosciences Montpellier - Université Montpellier 2 – 34090 Place Eugène Bataillon 2 CEREGE – Aix-en-Provence – 13545, Aix en Provence cedex 4

Mots clés : Tectonique active, cycle sismique, paléosismologie, modélisation numérique

La chaine himalayenne est une des régions à la surface de notre planète où les processus

climatiques et tectoniques sont les plus intenses. De nombreuses études menées depuis plus de

30 ans ont permis de documenter la déformation et les séismes majeurs associés de cette

région (M>8) (Chen & Molnar 1977; Schelling & Arita, 1991 ; Lavé & Avouac, 2000).

Bien qu’étant une zone clé pour l’étude des variations latérales le long de l’arc Himalayen, les

premières études de la déformation quaternaire au Bhoutan sont très récentes. Ainsi, Berthet

et al. 2014, à travers une analyse morphotectonique de la partie centrale du Bhoutan, montre

l'existence d'une déformation holocène équivalente à celle observée au Népal (deux séismes

majeurs (M>8) durant les derniers 1100 ans).

Nous proposons ici, d'affiner ces observations préliminaires, en quantifiant plus en détail cette

déformation. Les liens entre les procesus de dénudation et les processus tectonique

(mécanismes et géométries) sont abordés par une analyse des concentrations en 10Be des

sédiments de rivière, le long d'un transect latitudinal dense.

Une première analyse morphotectonique et paléosismologique détaillée de deux sites au front

a également été effectuée lors d'une première mission de terrain.

Le taux de soulèvement vertical ainsi obtenu, couplé à la géométrie des structures en surface,

puis en profondeur devrait aboutir à termes à l'estimation d'un taux de raccourcissement

horizontal qui sera comparé aux données GPS.


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47

Present-day strain partitioning and strain transfer across the

Fairweather and Denali Faults in SW Yukon – SE Alaska

Anaïs MARECHAL, [email protected]

Stéphane Mazzotti1, Jean-François Ritz1, Matthieu Ferry1

1 Géosciences Montpellier, Université Montpellier 2, Place E. Bataillon, 34 095 Montpellier

Keywords: partition, deformation, GPS, géomorphologie, modélisation

In SW Yukon – SE Alaska, the present-day Pacific – North America relative motion (~55

mm/yr) is highly oblique to the main plate boundary, resulting in strong strain-partitioning

tectonics that link the Aleutian subduction to the west to Queen Charlotte transform to the

south. This transition region is also the site of present-day orogeny (St Elias) and accretion of

the allochthonous Yakutat Terrane to the Northern Cordillera.

Multiple datasets (GPS, geomorphology, seismicity) are integrated to characterize and

quantify strain patterns in this transpressional system, with particular emphasis on strain

partitioning between strike-slip and shortening deformation. New campaign and permanent

GPS stations straddling the main faults (Denali, Fairweather: vertical lithospheric scale faults)

indicate that that 95% of the Pacific-North America strike-slip motion is accommodated on

the main plate-boundary Fairweather Fault, leaving near-zero motion on the Denali Fault only

~100 km inboard. In contrast, the fault-perpendicular component is strongly distributed

between shortening offshore and in the orogen, and 25% of the convergence transferred

inland. This latter strain transfer could explain the seismicity observed in the Mackenzie

Mountains 500 – 800 km from the coast.

In the region of highest convergence obliquity, GPS data show a diffuse indentor-like

deformation, with strong along-strike variations of the main fault slip rates. Preliminary

results of a regional geomorphology study give further information about the Denali fault,

along which previous data indicate a velocity decrease from 8 mm/yr (Matmon et al.,2006) to

4 mm/yr (Seitz et al., 2010) over 200 km along strike. A high resolution DEM (2m) processed

from Pleiades data acquired in September 2013 highlights a significant vertical component on

the Denali fault. Systematic metric scale displacements are measured along the “inactive” part

of the fault, showing recent deformation since the Last Glacial Maximum in the region (~20

kyrs ago). Sampling of geomorphological markers for Be10 and OSL datation is planned in the

summer 2014 in order to estimate slip rates along the southern part of the main transpressional

faults (Denali, Totschunda).


48

Figure 5: Schematic map of the indentor model and velocity results


49

Déformations extrêmement lentes et mouvement verticaux : apport du

GPS et du nivellement pour contraindre des modèles numériques

NGUYEN Hai Ninh1,2,3

Philippe Vernant1

Stéphane Mazzotti1

1 Géosciences Montpellier (France) ; 2 TOTAL E&P, Stavanger (Norway) ; 3 TOTAL SA, Pau (France)

Mots clés : Western Alpine, Pyrénées, GPS, déformation, mouvement, convergence

Les chaines de montagnes françaises sont caractérisées par une sismicité modérée et

une déformation horizontale qui ne peut pas pour l’instant être mise en évidence par

les mesures GPS. Seule la borne supérieure des conditions aux limites de ces chaines

peut être donné (±0.5 mm/an, ex. : Nocquet et Calais, 2003, 2004, Vernant, résultats

non publiés). Pourtant avec un séisme de magnitude 5 environ tous les 8 à 10 ans et

un de magnitude 6 tous les 150200 ans dans les Pyrénées (Souriau & Pauchet, 1998),

il semble évident que cette chaine se déforme encore de manière active, même si c’est

de manière très lente. Des résultats préliminaires de modélisation numérique

indiquent que cette déformation pourrait être due simplement à l’érosion. Dans ce cas

les vitesses verticales pourraient être bien supérieures aux vitesses horizontales. La

France est couverte par un réseau GNSS permanent (RGP), et des données sont

disponibles pour les pays limitrophes (Espagne, Italie, Suisse). L’objectif de la thèse

sera multiple :

- Traiter toutes les données du RGP pour identifier les sites stables analyser

précisément les séries temporelles des sites stables pour déterminer leur vitesse

verticale

- Retraiter les campagnes de nivellement disponibles pour la chaine des Pyrénées

- Développer des modèles numériques 3D de la déformation des Alpes et Pyrénées en

tenant compte de l’érosion

L’objectif de cette thèse est donc de mieux comprendre les mécanismes de

déformation des orogènes identifiés comme inactifs au sens des vitesses de

convergence aux limites et de préciser si l’on peut encore utiliser le paradigme de

l’effondrement gravitaire pour expliquer la phase terminale de démantèlement des

orogènes.


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Figure 1. Distribution of the permanent GNSS stations used in

this study. Stars show the International GNSS stations of the

IGS Network. Squares show the GNSS stations of the European

Network (EUREF-EPN). Circles show the GNSS stations of the

French permanent GNSS Network (RGP and RENAG

Network). Symbols are colored based on the length of the data

span for each station.

Fig. 10a, b RMS of convergent time of velocity(a) and 1 uncertainty(b) for North, East, Up and 2D component with respect to 7 different

convergent thresholds (1.0, 0.8, 06, 0.5, 0.4, 0.2 and 0.1 mm/yr) for all stations. Forward time solution is F-dashed line, Backward time

solution is B-dash-doted line and synthetic time solution is Solid Line. The blue, green, red and violet represent North, East, Up and 2D

component, respectively. The y axis is in mm/year and the x axis is convergent time span in decimal year.

Fig. 11a, b. Horizontal (a) and vertical (b) velocities (in mm/yr) in the Western Alps and the Pyrenees region. The horizontal

velocities and their 95% confidence ellipses are given with respect to the stable Eurasian plate described in this study. The vertical

velocities and their 1- uncertainty are in ITRF2008 reference frame. Blue arrows: horizontal velocities of GPS stations that

observed for more than 4.43 years; Red arrows: vertical velocities of GPS stations that observed for more than 4.78 years.


51

Imagerie de l’anisotropie sismique de la croûte – Exemple de la faille de

Denali : localisation de la déformation en profondeur à l’échelle

lithosphérique.

Nathalie RASENDRA1, [email protected]

Christel Tiberi1, Stéphane Mazzotti1

1Géosciences Montpellier UMR 5243 - CC 60 Université Montpellier 2 Place E. Bataillon 34095

Montpellier cedex 5

Mots clés : Anisotropie sismique, tomographie, corrélations, bruit ambiant, faille de Denali.

La faille de Denali est un décrochement intracontinental dextre s’étendant sur plusieurs

milliers de kilomètres. Elle accommode une partie de la convergence entre la plaque Pacifique

et la plaque Nord-Amérique. La déformation en surface y est distribuée tandis que sa structure

en profondeur est encore méconnue : imager l’anisotropie sismique pourrait contribuer à

comprendre son rôle dans la distribution de la déformation en surface et en profondeur à

l’échelle lithosphérique.

L’analyse des fonctions récepteur a mis en évidence une anisotropie sismique localisée dans

la croûte moyenne et dont la direction de polarisation rapide est parallèle à l’orientation de la

faille. D’ailleurs, cette direction est cohérente avec celle obtenue grâce aux mesures SKS.

Les contraintes sur la caractérisation de cette anisotropie marquée sont encore insuffisantes.

Nous avons donc décidé de coupler les résultats issus des fonctions récepteur avec un autre

outil d’imagerie sismique : la tomographie par corrélations de bruit ambiant. Cette technique

se base sur l’enregistrement continu du bruit ambiant de la Terre présent partout ce qui permet

de s’affranchir de l’occurrence des séismes.


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Légende : a) Topographie (du modèle 1 minute d’arc ETOPO1) et schéma géodynamique de

la région d’étude. Les triangles indiquent la localisation des stations sismiques utilisées pour

l’étude. Les principaux systèmes de failles sont en traits pleins (Rasendra and al., 2014

accepted).

b) Variations azimutales des fonctions récepteur sur les composantes radiale et transverse de

la station BVCY.


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Realistic simulation of instantaneous nearshore water levels during

typhoons

Fabien Rétif 1 , Frédéric Bouchette 1 , Jiing-Yih Liou 2 , Samuel Meulé 3 , Héloïse Michaud 4 ,

Li-Ching Lin 5 , Kao-Shu Hwang 2 , Nans Bujan 2 , Hwung-Hweng Hwung 6 and the

SIROCCO Team 7

1. Géosciences-M, UMR 5243, University Montpellier 2 & CNRS, 34095 Montpellier, France 2. Tainan Hydraulics Laboratory, National Cheng Kung University, Taiwan 3. Aix-Marseille Université, CNRS, IRD, CEREGE UM34, Aix en Provence, France 4. SHOM, 42 avenue Gaspar Coriolis, 31157 Toulouse Cedex, France 5. International Wave Dynamics Research Center, National Cheng Kung University, Taiwan 6. Department of Hydraulic and Ocean Engineering, National Cheng Kung University, Taiwan 7. Laboratoire d’Aérologie – CNRS & University of Toulouse, 14, Avenue Edouard Belin, 31400 Toulouse,

France

Mots clés: instantaneous water level, wind, wave, current, typhoon, extreme phenomena

3D hydrodynamics simulations were performed on an area covering 600 km around the

Taiwan island (figure 1A) for the period running from September to October 2011. These

simulations discuss the regional hydrodynamic mechanisms which control the sea surface

elevation along the Wan-Tzu-Liao sand barrier (south-west Taiwan).

METHODOLOGY

The simulation is based on SYMPHONIE (Marsaleix et al., 2008), a robust 3D circulation

model dealing with most of the oceanographical forcings (winds, air/sea fluxes), global scale

circulation (tides, Kuroshio current), rivers and waves. In the framework of the KUNSHEN

project (ANR/NSC), a raft of devices were set in front of the Wan-Tzu Liao barrier during 7

months of monitoring including the simulated period. The equipments were deployed along a

cross-shore section (in 18 m, 7 m, 4 m of water depth and on the emerged beach) and

provided robust informations on nearshore hydrodynamics and water levels. We confront

these measurements to the simulated instantaneous water levels, surface and bottom current

velocities to validate the model with a particular emphasis on water level to the shoreline.

RESULTS

The figure 1B shows the sea surface elevation (at the 18m buoy) controlled by tide (harmonic

reanalysis from FES2012), global currents (MERCATOR) and atmospheric conditions

(ECMWF). The maximal elevation generated by the tide is 77 cm. For global currents, the

mean elevation is 70 cm and the maximal is 84 cm. Regarding the atmospheric forcings, the

maximal elevation is 19 cm and the mean elevation is 10 cm. We show that tides and global

currents control mainly the sea surface elevation; but for the analysis of the submersion, it is

also important to take into account the effect of atmospheric conditions. Regardless the wave

effect, the simulation reproduces correctly the measures with a quality equivalent to that

observed in Michaud et al, (2012) in the Gulf of Lions (France).


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Figure 1 – A) The polar grid with a nearshore resolution of 460 m and 5.6 km at the offshore,

and the typhoon tracks during the considered period; B) analysis of the sea surface elevation

according to the forcings at the 18 m buoy of water depth.

REFERENCES

Marsaleix P., Auclair F., Floor J. W., Herrmann M. J., Estournel C., Pairaud I. and Ulses C.

(2008):Energy conservation issues in sigma-coordinate free-surface ocean models, Ocean

Modelling, Vol. 20, pp. 61–89.

Michaud H., Marsaleix P., Leredde Y., Estournel C., Bourrin F., Lyard F., Mayet C., Ardhuin

F. (2012): Three-dimensional modelling of wave-induced current from the surf zone to the

inner shelf, Ocean Science, Vol. 8, pp. 657-681.

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