Résumé : Photo date stamped on back: April 11, 1980.
(Biographical) "34 true Cuban patriots ... are starving themselves as they say the thousands of their brothers and sisters trapped in the Peruvian Embassy in Havana are starving. ... 'I no work until I have an answer from the governments and from the world,' said 56-year-old Angel Urquiloa." -- Article by Jack Knarr in the Miami News, April 10, 1980, p. 4A.
(Biographical) In early April 1980, the Cuban government announced that anyone wishing to leave the country should go to the Peruvian Embassy. Within two days about 10,000 Cubans entered the grounds. On April 20, Castro announced that all who wished to leave could board boats at the port of Mariel. Thus began the Mariel Boatlift.
(Preferred Citation) Cite as Miami News Collection, HistoryMiami, 1995-277-3047.
Cuba

Droits : All rights reserved by the source institution.
1995-277-3047
http://ufdc.ufl.edu/AA00015765/00001

Résumé : Tampa's cigar workers followed the direction of their own independent union, popularly known as La Resistencia, in the general strike of 1901.The major dispute in 1901 involved efforts of manufacturers to establish branch factories in Pensacola and Jacksonville. The union interpreted these moves as an attempt to maintain an open shop policy and struck to force a closing of these operations. Strike leadership was in Spanish and Cuban hands, but Italians were active in the ranks and in supplying street-corner oratory that helped to maintain worker solidarity. Appeals to the strike cause were effective in prompting numerous workers to leave Tampa and find employment elsewhere in an effort to send back support
(Funding) Funded in part by the Institute for Museum and Library Services (IMLS), Ephemeral Cities Project.
Tampa |z 1271000 |2 ceeus
Hillsborough County |z 12057 |2 ceeus
United States of America -- Florida -- Hillsborough County -- Tampa
21st Street

Droits : All rights reserved. 2005.
P21-0252

Éditeur(s) : Cultural Cultural ( Habana )
Cuba
Labor laws and legislation
Cuba

000661674
23830422
ADK1925

Résumé : Don Vicente was entertaining Ignacio Haya, a manufacturing friend from New York, when Gargol and Gutierrez arrived. Haya, of the firm Sanchez and Haya, had come to Key West for both business and pleasure; he always enjoyed the warm Florida climate. Sr. Haya was also there to discuss business. Both he and Ybor were constantly being threatened with labor strikes which could cripple their operations. Haya saw the problem as so serious that he had already dispatched his associate, Serafin Sanchez, to search for other possible locations to open branch factories.8 Don Vicente was also confronted with labor hostility in Key West, and he too wanted to move to a location where labor was not organized. They were undoubtedly influenced by other manufacturers who were forming company towns, away from the crowded cities, as a means of accelerating production and limiting union influence. Ybor and Haya sent inquiries to Galveston, Mobile, and Pensacola, expressing their interests in possibly locating in one of those cities. Don Vicente had earlier learned about Tampa from Edward Manrara, but had not yet given it serious consideration as a possible location for a branch factory; not until the visit of Gutierrez and Gargol.
(Funding) Funded in part by the Institute for Museum and Library Services (IMLS), Ephemeral Cities Project.
Tampa |z 1271000 |2 ceeus
Hillsborough County |z 12057 |2 ceeus
United States of America -- Florida -- Hillsborough County -- Tampa

Droits : All rights reserved. 2005.
C24-05713

Éditeur(s) : HAL CCSD
Résumé : The Karakorum Fault zone (KFZ), lying in the west of the Tibetan plateau, is an important dextral strike-slip fault and the important northern geological boundary of the west Himalaya. In the AyilaRi' gyu Range-Gai Basin area lying in the southeast of the KFZ, Ar-40/Ar-39 thermochronologic analysis was performed on the syn-tectonic minerals in the, metamorphic rocks in the Karakorum ductile shear zone, with the base of petrology and deformation structure researches. According to the microstructure features, the minerals in the shear zone recorded the continuous deformation from high ( > 600 degrees C) to low temperature ( < 250 degrees C) appeared as that the nearly horizontal dextral shearing has transformed into the oblique dextral normal slip, made the greenschist facies of deformation stack oil the early medium-high temperature deformation, indicated the uplift during the slip. The thermochronologic revealed the continuous shear process from the early Miocene to 4Ma at least, which containing three rapid cooling stage: from 25 similar to 22Ma to 21 similar to 18Ma, the deformation locally stopped or slower in the, shallow high temperature shear process; from 15Ma to 12Ma, the rapid uplift of the AyilaRi' gyu Range, the initial formation of the Gar Basin together with the main deep incision of river during the strip-slip of the KFZ; since 9Ma, the AyilaRi' gyu Range has increased the rapid uplift and the Gar Basin has formed finally. According to the different levels of deformation and the dextral displacement of the surface landform with different ages, the long term slip rate and the uplift rate indicated the intense dextral strike slip and uplift associated since the late Quarternary Period.
Acta Petrologica Sinica

hal-00411572
https://hal.archives-ouvertes.fr/hal-00411572

Éditeur(s) : HAL CCSD Elsevier
Résumé : We use a triangular representation of the plunges of P, B, and Taxes to compare the different ways tectonic regime is inferred from earthquake focal mechanisms in recent works. We argue that P, B, and Taxes provide a reasonable estimate of principal stress directions when faulting is close to Andersonian conditions, and that this can be estimated from the location on a triangular diagram. We analyze the geometrical relationship between the plunges of P, B, and Taxes on one hand, and the rake of slip and dip of nodal planes on the other hand. We show that the rake and dip level curves correspond to trajectories of the vertical direction along great and small circles with respect to the frame of the P, B. and Taxes. This shows that dip-slip faulting is compatible with vertical P or Taxes, but does not require it, and instead requires horizontal B axes. It also shows that strike-slip faulting does not require vertical B axes, but P and Taxes with equal plunges. This also reveals that focal mechanisms where P, B, and Taxes all have moderate plunge correspond to two very different types of nodal planes: a steeply dipping one with oblique slip and a moderately dipping one with strike-slip. Seismically active and moderately dipping strike-slip faults are to be found among these events.
ISSN: 0040-1951

hal-00486367
https://hal.archives-ouvertes.fr/hal-00486367
DOI : 10.1016/j.tecto.2009.03.006

Éditeur(s) : Public Library Science
Résumé : Biological invasions rank amongst the most deleterious components of global change inducing alterations from genes to ecosystems. The genetic characteristics of introduced pools of individuals greatly influence the capacity of introduced species to establish and expand. The recently demonstrated heritability of microbial communities associated to individual genotypes of primary producers makes them a potentially essential element of the evolution and adaptability of their hosts. Here, we characterized the bacterial communities associated to native and non-native populations of the marine green macroalga Caulerpa racemosa through pyrosequencing, and explored their potential role on the strikingly invasive trajectory of their host in the Mediterranean. The similarity of endophytic bacterial communities from the native Australian range and several Mediterranean locations confirmed the origin of invasion and revealed distinct communities associated to a second Mediterranean variety of C. racemosa long reported in the Mediterranean. Comparative analysis of these two groups demonstrated the stability of the composition of bacterial communities through the successive steps of introduction and invasion and suggested the vertical transmission of some major bacterial OTUs. Indirect inferences on the taxonomic identity and associated metabolism of bacterial lineages showed a striking consistency with sediment upheaval conditions associated to the expansion of their invasive host and to the decline of native species. These results demonstrate that bacterial communities can be an effective tracer of the origin of invasion and support their potential role in their eukaryotic host's adaptation to new environments. They put forward the critical need to consider the 'meta-organism' encompassing both the host and associated micro-organisms, to unravel the origins, causes and mechanisms underlying biological invasions.
Plos One (1932-6203) (Public Library Science), 2013-07 , Vol. 8 , N. 7 , P. -

Droits : 2013 Aires et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
http://archimer.ifremer.fr/doc/00157/26791/24886.pdf
DOI:10.1371/journal.pone.0068429
http://archimer.ifremer.fr/doc/00157/26791/

Éditeur(s) : American Geophysical Union
Résumé : We present new high-resolution bathymetry and backscatter data acquired in 2006 with the ROV Victor 6000 over the Lucky Strike hydrothermal field, Mid-Atlantic Ridge. As long-term monitoring of the Lucky Strike area (MoMAR project) is being implemented, these new high-resolution data offer an unprecedented view of the distribution of hydrothermal edifices, eruptive facies, and small-scale tectonic features in the Lucky Strike vent field. We show that vents located in the NW and NE correspond with wide expanses of lumpy seafloor which we interpret as primarily made of broken chimneys and sulfide edifices. They are found above scarps with relief > 50 m or on associated mass wasting deposits. By contrast, the SE and SW vents correspond with small expanses of lumpy seafloor and are located near smaller scarps which we interpret as more recent faults. Hydrothermal edifices in the SW venting area appear very recent, postdating the emplacement and faulting of the most recent lava. We propose that this difference in the age of hydrothermal edifices does not mean that hydrothermal venting itself is more recent in the southern part of the Lucky Strike field because preexisting sulfide deposits there may have been buried by recent volcanic deposits. Instead, the older edifices in the northern part of the hydrothermal field may have been allowed more time to grow because they are set above the level of recent lava flows. The formation of a lava lake is the most recent eruptive event detected at Lucky Strike. Lava drainback is evidenced by benches and lava pillars, suggesting a close connection with an underlying magma reservoir, which probably corresponds to the melt body imaged by Singh et al. (2006). We have found no evidence that this lake was active for months to decades, as lava lakes at terrestrial volcanoes. It may instead have formed as a lava pond, with successive lava flows covering the eruptive vents, as proposed for similar features at the EPR. The horizontal surface of the lake is deformed only near its southwestern shore, along a NNE-trending set of faults and fissures, which appear to control the distribution of hydrothermal chimneys.
Geochemistry Geophysics Geosystems (1525-2027) (American Geophysical Union), 2009-02 , Vol. 10 , N. 2 , P. 1-18

Droits : 2009 American Geophysical Union
http://archimer.ifremer.fr/doc/2009/publication-6161.pdf
DOI:10.1029/2008GC002171
http://archimer.ifremer.fr/doc/00000/6161/

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
We carried out morphotectonic studies along the left-lateral strike-slip Bogd Fault, the principal structure involved in the Gobi-Altay earthquake of 1957 December 4 (published magnitudes range from 7.8 to 8.3). The Bogd Fault is 260 km long and can be subdivided into five main geometric segments, based on variation in strike direction. West to East these segments are, respectively: the West Ih Bogd (WIB), The North Ih Bogd (NIB), the West Ih Bogd (WIB), the West Baga Bogd (WBB) and the East Baga Bogd (EBB) segments. Morphological analysis of offset streams, ridges and alluvial fans-particularly well preserved in the arid environment of the Gobi region-allows evaluation of late Quaternary slip rates along the different faults segments. In this paper, we measure slip rates over the past 200 ka at four sites distributed across the three western segments of the Bogd Fault. Our results show that the left-lateral slip rate is similar to 1 mm yr(-1) along the WIB and EIB segments and similar to 0.5 mm yr(-1) along the NIB segment. These variations are consistent with the restraining bend geometry of the Bogd Fault.;Our study also provides additional estimates of the horizontal offset associated with the 1957 earthquake along the western part of the Bogd rupture, complementing previously published studies. We show that the mean horizontal offset associated with the 1957 earthquake decreases progressively from 5.2 m in the west to 2.0 m in the east, reflecting the progressive change of kinematic style from pure left-lateral strike-slip faulting to left-lateral-reverse faulting. Along the three western segments, we measure cumulative displacements that are multiples of the 1957 coseismic offset, which may be consistent with a characteristic slip. Moreover, using these data, we re-estimate the moment magnitude of the Gobi-Altay earthquake at M-w 7.78-7.95.;Combining our slip rate estimates and the slip distribution per event we also determined a mean recurrence interval of similar to 2500-5200 yr for past earthquakes along the different segments of the western Bogd Fault. This suggests that the three western segments of the Bogd Fault and the Gurvan Bulag thrust fault (a reverse fault bounding the southern side of the Ih Bogd range that ruptured during the 1957 earthquake) have similar average recurrence times, and therefore may have ruptured together in previous earthquakes as they did in 1957. These results suggest that the western part of the Bogd Fault system, including the Gurvan Bulag thrust fault, usually behaves in a 'characteristic earthquake' mode.
ISSN: 0956-540X

hal-00639467
https://hal.archives-ouvertes.fr/hal-00639467
https://hal.archives-ouvertes.fr/hal-00639467v2/document
https://hal.archives-ouvertes.fr/hal-00639467/file/rizzaGJI2011.pdf
DOI : 10.1111/j.1365-246X.2011.05075.x

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The NW-trending Talas-Ferghana Fault (TFF) in Kyrgyzstan, Central Asia, is one of the largest intracontinental strike-slip faults in the world. It extends over a distance of more than 2000 km from southern Tourghai to western Tarim and exhibits a maximum dextral offset of ∼200 km during the late Palaeozoic to present. The history of the fault provides important insights for the understanding of the evolution of southern Central Asia but remains poorly constrained due to lack of reliable geochronological data. We present new Ar-Ar ages and structural data from the Kyrgyz West Tianshan, that elucidate the kinematic history of the TFF in the Palaeozoic and Mesozoic. 40Ar/39Ar ages on mylonitic white micas document a deformational history consisting of several episodes. A late Carboniferous age of 312 ± 4 Ma point to initiation of top-to-the-south and dextral transpressional deformation during a metamorphic overprint in Precambrian and Palaeozoic rocks along the northern compartment of the TFF. The main phase of dextral motion along the entire fault occurred in the Permian as suggested by minimum ages of 260-290 Ma obtained at two different locations in the NW and central parts of the TFF. Partial isotopic resetting occurred between 240 and 210 Ma and younger ages of <200-210 Ma are ascribed to late brittle reactivation and hydrothermal fluid flow in the Late Triassic to Early Jurassic times. The Jurassic trans-tensional phase is featured by emplacement of 195 ± 3 Ma pegmatitic dykes. The Ar-Ar mineral ages and structural data argue for a major phase of dextral shearing, affecting the entire region from the West Tianshan to Mongolia in the late Permian and leading to formation of almost equally spaced major NW-trending dextral strike-slip faults. The uniform character of this deformation indicates that the process of amalgamation in this part of the CAOB ended prior to the late Permian, and Central Asia evolved as a single coherent continental block since that time.
ISSN: 0743-9547

hal-00831326
https://hal.archives-ouvertes.fr/hal-00831326
DOI : 10.1016/j.jseaes.2013.02.012

Éditeur(s) : HAL CCSD Taylor & Francis: SSH Journals
Résumé : International audience
We investigated the oxygen-conserving potential of the human diving response by comparing trained breath-hold divers (BHDs) to non-divers (NDs) during simulated dynamic breath-holding (BH). Changes in haemodynamics [heart rate (HR), stroke volume (SV), cardiac output (CO)] and peripheral muscle oxygenation [oxyhaemoglobin ([HbO2]), deoxyhaemoglobin ([HHb]), total haemoglobin ([tHb]), tissue saturation index (TSI)] and peripheral oxygen saturation (SpO2) were continuously recorded during simulated dynamic BH. BHDs showed a breaking point in HR kinetics at mid-BH immediately preceding a more pronounced drop in HR (−0.86 bpm.%−1) while HR kinetics in NDs steadily decreased throughout BH (−0.47 bpm.%−1). By contrast, SV remained unchanged during BH in both groups (all P > 0.05). Near-infrared spectroscopy (NIRS) results (mean ± SD) expressed as percentage changes from the initial values showed a lower [HHb] increase for BHDs than for NDs at the cessation of BH (+24.0 ± 10.1 vs. +39.2 ± 9.6%, respectively; P < 0.05). As a result, BHDs showed a [tHb] drop that NDs did not at the end of BH (−7.3 ± 3.2 vs. −3.0 ± 4.7%, respectively; P < 0.05). The most striking finding of the present study was that BHDs presented an increase in oxygen-conserving efficiency due to substantial shifts in both cardiac and peripheral haemodynamics during simulated BH. In addition, the kinetic-based approach we used provides further credence to the concept of an “oxygen-conserving breaking point” in the human diving response.
ISSN: 0264-0414

hal-01325466
https://hal-univ-perp.archives-ouvertes.fr/hal-01325466
DOI : 10.1080/02640414.2016.1183809

Éditeur(s) : HAL CCSD Oxford University Press (OUP): Policy B - Oxford Open Option A Oxford University Press (OUP)
Résumé : International audience
Peridotite xenoliths exhumed by Quaternary alkaline magmatism in the Tahalgha district, southern Hoggar, represent fragments of the subcontinental lithospheric mantle beneath the boundary between the two major structural domains of the Tuareg Shield: the ‘Polycyclic Central Hoggar’ to the east and the ‘Western Hoggar’, or ‘Pharusian Belt’, to the west. Samples were collected from volcanic centres located on both sides of a major lithospheric shear zone at 4°35' separating these two domains. Although showing substantial variations in their deformation microstructures, equilibrium temperatures and modal and chemical compositions, the studied samples do not display any systematic changes of these features across the 4°35' fault. The observed variations rather record small-scale heterogeneities distributed throughout the study area and reflecting the widespread occurrence of vein conduits and metasomatized wall-rocks related to trans-lithospheric melt circulation during the Cenozoic. These features include partial annealing of pre-existing deformation microstructures, post-deformation metasomatic reactions, and trace-element enrichment, coupled with heating from 750–900°C (low-temperature lherzolites) to 900–1150°C (intermediate-T lherzolites and high-T harzburgites and wehrlites). Trace-element modelling confirms that the range of rare earth element (REE) variations observed in the Tahalgha clinopyroxenes may be accounted for by reactive porous flow involving a single stage of basaltic melt infiltration into a light REE (LREE)-depleted protolith. Whole-rock compositions record the final entrapment of disequilibrium metasomatic melts upon thermal relaxation of the veins–wall-rock system. The striking correlations between equilibrium temperatures and trace-element enrichment favor a scenario in which the high-temperature peridotites record advective heat transport along melt conduits, whereas the intermediate- and low-temperature lherzolites reflect conductive heating of the host Mechanical Boundary Layer. This indicates that the lithosphere did not reach thermal equilibrium, suggesting that the inferred heating event was transient and was rapidly erased by thermal relaxation down to the relatively low-temperature present-day geotherm. The low-T (<900°C) deformed lherzolites (porphyroclastic to equigranular) are characterized by only incipient annealing and LREE-depleted clinopyroxene compositions. They were only weakly affected by the Cenozoic events and could represent relatively well-preserved samples from rejuvenated Pan-African lithosphere. Extensive lithospheric rejuvenation occurred either regionally during the Pan-African orogeny, as a result of lithospheric delamination or thermomechanical erosion after thickening, or more locally along the meridional shear zones. The low-T Tahalgha lherzolites are comparable with lherzolites from Etang de Lherz, southern France, interpreted as lithospheric mantle rejuvenated by melt-induced refertilization during a late stage of the Variscan orogeny.
ISSN: 0022-3530

hal-01107410
https://hal.archives-ouvertes.fr/hal-01107410
DOI : 10.1093/petrology/egu056

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : Approximately 4 yr of campaign and continuous Global Positioning System (GPS) measurements across the Dead Sea fault system (DSFS) in Lebanon provide direct measurements of interseismic strain accumulation along a 200-km-long restraining bend in this continental transform fault. Late Cenozoic transpression within this restraining bend has maintained more than 3000 m of topography in the Mount Lebanon and Anti-Lebanon ranges. The GPS velocity field indicates 4-5 mm yr(-1) of relative plate motion is transferred through the restraining bend to the northern continuation of the DSFS in northwestern Syria. Near-field GPS velocities are generally parallel to the major, left-lateral strike-slip faults, suggesting that much of the expected convergence across the restraining bend is likely accommodated by different structures beyond the aperture of the GPS network (e.g. offshore Lebanon and, possibly, the Palmyride fold belt in SW Syria). Hence, these geodetic results suggest a partitioning of crustal deformation involving strike-slip displacements in the interior of the restraining bend, and crustal shortening in the outer part of the restraining bend. Within the uncertainties, the GPS-based rates of fault slip compare well with Holocene-averaged estimates of slip along the two principal strike-slip faults: the Yammouneh and Serghaya faults. Of these two faults, more slip occurs on the Yammouneh fault, which constitutes the primary plate boundary structure between the Arabia and Sinai plates. Hence, the Yammouneh fault is the structural linkage that transfers slip to the northern part of the transform in northwestern Syria. From the perspective of the regional earthquake hazard, the Yammouneh fault is presently locked and accumulating interseismic strain.
ISSN: 0956-540X

hal-00406620
https://hal.archives-ouvertes.fr/hal-00406620
DOI : 10.1111/j.1365-246X.2006.03328.x

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Mosha and North Tehran faults correspond to the nearest seismic sources for the northern part of the Tehran megacity. The present-day structural relationships and the kinematics of these two faults, especially at their junction in Lavasanat region, is still a matter of debate. In this paper, we present the results of a morphotectonic analysis (aerial photos and field investigations) within the central part of the Mosha and eastern part of the North Tehran faults between the Mosha valley and Tehran City. Our investigations show that, generally, the traces of activity do not follow the older traces corresponding to previous long-term dip-slip thrusting movements. The recent faulting mainly occurs on new traces trending E-W to ENE-WSW affecting Quaternary features (streams, ridges, risers, and young glacial markers) and cutting straight through the topography. Often defining en-echelon patterns (right- and left-stepping), these new traces correspond to steep faults with either north- or south-dipping directions, along which clear evidences for left-lateral strike-slip motion are found. At their junction zone, the two sinistral faults display a left-stepping en-echelon pattern defining a positive flower structure system clearly visible near Ira village. Further west, the left-lateral strike-slip motion is transferred along the ENE-WSW trending Niavaran fault and other faults. The cumulative offsets associated with this left-lateral deformation is small compared with the topography associated with the previous Late Tertiary thrusting motion, showing that it corresponds to a recent change of kinematics.
ISSN: 0040-1951

hal-00617778
https://hal.archives-ouvertes.fr/hal-00617778
DOI : 10.1016/j.tecto.2010.09.013

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Lithospheric-scale faults related to oblique subduction are responsible for some of the most hazardous earthquakes reported worldwide. The mega-thrust in the Sunda sector of the Sumatran oblique subduction has been intensively studied, especially after the infamous 2004 Mw 9.1 earthquake, but its onshore kinematic complement within the Sumatran subduction, the transform Sumatran Fault System, has received considerably less attention. In this paper, we apply a combination of analysis of Digital Elevation Models (ASTER GDEM) and field evidence to resolve the kinematics of the leading edge of deformation of the northern sector of the Sumatran Fault System. To this end, we mapped the northernmost tip of Sumatra, including the islands to the northwest, between 4.5°N and 6°N. Here, major topographic highs are related to different faults. Using field evidence and our GDEM structural mapping, we can show that in the area where the fault bifurcates into two fault strands, two independent kinematic regimes evolve, both consistent with the large-scale framework of the Sumatran Fault System. Whereas the eastern branch is a classic Riedel system, the western branch features a fold-and-thrust belt. The latter contractional feature accommodated significant amounts (c. 20%) of shortening of the system in the study area. Our field observations of the tip of the NSFS match a strain pattern with a western contractional domain (Pulau Weh thrust splay) and an eastern extensional domain (Pulau Aceh Riedel system), which are together characteristic of the tip of a propagating strike-slip fault, from a mechanical viewpoint. For the first time, we describe the strain partitioning resulting from the propagation of the NSFS in Sumatra mainland. Our study helps understanding complex kinematics of an evolving strike-slip system, and stresses the importance of field studies in addition to remote sensing and geophysical studies.
ISSN: 0040-1951

hal-01467196
https://hal.archives-ouvertes.fr/hal-01467196
DOI : 10.1016/j.tecto.2016.04.050

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We use a strike-slip fault analog model to study experimentally the role played by along-fault non-uniform and asymmetric applied normal stress on both coseismic slip and long-term fault behavior. Our model is based on a visco-elasto-plastic multi-layered rheology that allows to produce several hundreds of scaled analog microquakes and associated seismic cycles. Uniform or heterogeneous applied normal stress along the fault plane is imposed and maintained constant during the whole experiment durations. Our results suggest that coseismic slip patterns are strongly controlled by spatial normal stress variations and subsequent accumulated shear stress along fault strike. Major microquakes occur preferentially in zones of major shear stress asperities. Coseismic slip distributions exhibit a pattern similar to the along-fault applied normal stress distribution. The occurrence of isolated low to moderate microquakes where residual stresses persist around secondary stress asperities, indicates that stress conditions along the fault also control the whole variability of fault slip events. Moreover, when fault slip stability conditions are modulated by normal stress distribution, our experiments suggest that the along-fault stress heterogeneity influences the seismic cycle regularity and, consequently, long-term fault slip behavior. Uniform applied normal stress favors irregular seismic cycles and the occurrence of earthquakes clustering, whereas non-uniform normal stress with a single high amplitude stress asperity generates strong characteristic microquake events with stable return periods. Together our results strengthen the assumption that coseismic slip distribution and earthquake variability along an active fault may provide relevant information on long term tectonic stress and could thus improve seismic hazard assessment.
ISSN: 0012-821X

hal-01666379
https://hal.archives-ouvertes.fr/hal-01666379
DOI : 10.1016/j.epsl.2017.10.009

Éditeur(s) : HAL CCSD
Résumé : The aim of this thesis is to analyze the variations in slip rates along strike-slip faults, in intracontinental domain, producing large earthquakes (M > 7.5). To illustrate these variations, this work has focused in two area located in the most tectonically active continental domains in the world: in the western part of Mongolia (Bogd and Bulnay faults) and in the northern part of Iran (Astaneh and Tabriz faults). Using morphotectonic and paleoseismological analyses, the kinematics, the slip rates and the recurrence times have been estimated and allow us to describe the characteristics of seismic cycle along these faults. In Mongolia, the slip rates are estimated at ~ 1,2 and ~ 2,6 mm/yr along the Bogd and the Bulnay faults, respectively, with no variations of geological slip rates over the late Pleistocene-Holocene period. These two faults present characteristic slips and similar recurrence times between large earthquakes. The paleoseismological investigations suggest that a cluster occurred 3000 years ago, similar to the seismic cluster recorded in Mongolia during the XX century. In Iran, the slip rate was estimated to 2 mm/yr along the Astaneh fault and the recurrence times are ranging from 1600 to 2200 years, associated with offsets comprised between 3 and 4,5 m. We have also estimated a slip rate of ~ 7 mm/yr along the Tabriz fault, in agreement with the present day rate estimated by GPS, suggesting no variations in the slip rate over the past 45 ka.
Ce travail de thèse a pour but d'analyser les variations de vitesses sur des grandes failles décrochantes en contexte intracontinental, capables de produire des séismes de très fortes magnitudes (M > 7.5). Afin d'illustrer ces variations d'activités, cette analyse a été effectuée sur deux zones d'études situées en domaine continental et sismiquement actives: la région ouest de la Mongolie (failles de Bogd et Bolnay) et le nord de l'Iran (failles d'Astaneh et de Tabriz). À partir d'une approche morphotectonique et paléosismologique, les cinématiques, les vitesses de failles et les intervalles de récurrence entre les séismes majeurs ont été estimés, permettant d'analyser les caractéristiques du cycle sismique sur chacune des failles. En Mongolie, les failles de Bogd et Bolnay présentent respectivement des vitesses de ~ 1,2 et 2,6 mm/an, qui semblent être constantes sur la période Pleistocène supérieur-Holocène. Ces deux failles présentent également des glissements caractéristiques et des intervalles de temps similaires entre les séismes majeurs. Les analyses paléosismologiques suggèrent qu'un essaim sismique comparable à celui enregistré au XXème siècle a eu lieu il y a environ 3000 ans. En Iran, une vitesse géologique de 2 mm/an a été estimée sur la faille d'Astaneh et les données paléosismologiques suggèrent des intervalles de récurrence de 1800 ans, associés à des déplacements en surface compris entre 3 et 4,5 m. Nous avons également estimé une vitesse de 7 mm/an sur la faille de Tabriz, en accord avec les données GPS, suggérant que la vitesse sur cette faille est constante depuis 45 ka.
https://tel.archives-ouvertes.fr/tel-00591794

tel-00591794
https://tel.archives-ouvertes.fr/tel-00591794
https://tel.archives-ouvertes.fr/tel-00591794/document
https://tel.archives-ouvertes.fr/tel-00591794/file/these_rizza.pdf

Éditeur(s) : HAL CCSD American Geophysical Union (AGU)
Résumé : International audience
Subduction of a narrow slab of oceanic lithosphere beneath a tightly curved orogenic arc requires the presence of at least one lithospheric scale tear fault. While the Calabrian subduction beneath southern Italy is considered to be the type example of this geodynamic setting, the geometry, kinematics and surface expression of the associated lateral, slab tear fault offshore eastern Sicily remain controversial. Results from a new marine geophysical survey conducted in the Ionian Sea, using high-resolution bathymetry and seismic profiling reveal active faulting at the seafloor within a 140 km long, two-branched fault system near Alfeo Seamount. The previously unidentified 60 km long NW trending North Alfeo Fault system shows primarily strike-slip kinematics as indicated by the morphology and steep-dipping transpressional and transtensional faults. Available earthquake focal mechanisms indicate dextral strike-slip motion along this fault segment. The 80 km long SSE trending South Alfeo fault system is expressed by one or two steeply dipping normal faults, bounding the western side of a 500+ m thick, 5 km wide, elongate, syntectonic Plio-Quaternary sedimentary basin. Both branches of the fault system are mechanically capable of generating magnitude 6–7 earthquakes like those that struck eastern Sicily in 1169, 1542, and 1693.
ISSN: 0278-7407

insu-01256887
https://hal-insu.archives-ouvertes.fr/insu-01256887
https://hal-insu.archives-ouvertes.fr/insu-01256887/document
https://hal-insu.archives-ouvertes.fr/insu-01256887/file/GutscherEtal_2015_Tectonics.pdf
DOI : 10.1002/2015TC003898

Éditeur(s) : HAL CCSD Seismological Society of America
Résumé : With the assistance of the ASTER team (M. Arnold, G. Aumaître, D. Bourlès, and K. Keddadouche)
International audience
The Bulnay earthquake of 23 July 1905 (Mw 8.3–8.5), in north‐central Mongolia, is one of the world’s largest recorded intracontinental earthquakes and one of four great earthquakes that occurred in the region during the twentieth century. The 375 km long surface rupture of the left‐lateral, strike‐slip, N095°E‐trending Bulnay fault associated with this earthquake is remarkable for its pronounced expression across the landscape and for the size of features produced by previous earthquakes. Our field observations suggest that in many areas the width and geometry of the rupture zone is the result of repeated earthquakes; however, in those areas where it is possible to determine that the geomorphic features are the result of the 1905 surface rupture alone, the size of the features produced by this single earthquake are singular in comparison to most other historical strike‐slip surface ruptures worldwide. Along the 80 km stretch, between 97.18° E and 98.33° E, the fault zone is characterized by several meters width and the mean left‐lateral 1905 offset is 8.9±0.6  m with two measured cumulative offsets that are twice the 1905 slip. These observations suggest that the displacement produced during the penultimate event was similar to the 1905 slip. Morphotectonic analyses carried out at three sites along the eastern part of the Bulnay fault allow us to estimate a mean horizontal slip rate of 3.1±1.7  mm/yr over the Late Pleistocene–Holocene period. In parallel, paleoseismological investigations show evidence for two earthquakes prior to the 1905 event, with recurrence intervals of ∼2700–4000  yrs.
ISSN: 0037-1106

hal-01179837
https://hal.archives-ouvertes.fr/hal-01179837
https://hal.archives-ouvertes.fr/hal-01179837v2/document
https://hal.archives-ouvertes.fr/hal-01179837/file/rizza2015.pdf
DOI : 10.1785/0120140119

Éditeur(s) : HAL CCSD MAIK Nauka/Interperiodica
Résumé : International audience
The paper is concerned with the kinematics of the major faults, their pattern, and the time of occurrence of compression and extension deformations in the southeast of the Eastern Sayan. The geometry of the mountain ranges and the kinematics of the major faults exhibit northeast-oriented compression responsible for the current processes of relief formation, which corresponds to the direction of the vector of deformations associated with the Indo-Asian collision. The results obtained thus far may be indicative of the remote influence of collision on the orogenic activity and transpressional deformations in the Eastern Sayan since the end of the Miocene. Morphotectonic analysis has shown that the areas of Quaternary extension- related deformations in the Eastern Sayan are not a response to active rifting in the Baikal Rift Zone. The position and geometry of the subsided blocks and magma ruptures point to the fact that they form locally as extension structural elements near the strike-slip faults. The strike-slip and thrust faults are widespread and play the leading role in the development of the southeastern part of the Eastern Sayan.
ISSN: 0016-8521

insu-00667345
https://hal-insu.archives-ouvertes.fr/insu-00667345
DOI : 10.1134/S001685211101002X