Остаточные смещения, деформации и наклоны поверхности земли, связанные с сильными землетрясениями

ძლიერი მიწისძვრებით გამოწვეული ნარჩენი გადაადგილებების, დეფორმაციების და დახრების გამოსათვლელად გამოყენებულია სტეკეტის, ჩინერის და მარუიამის მიერ შემოთავაზებული რღვევების დისლოკაციის თეორია.

Некоторые статистические результаты для выявления экзогенных факторов землетрясений Кавказа

ნაშრომში შესწავლილია პლანეტებისა და მათი წყვილების ცის თაღზე განაწილება კავკასიის ძლიერი მიწისძვრების მოხდენის მომენტში.

Sequencing lifeline repairs after an earthquake: an economic approach

Recoveries after recent earthquakes in the U.S. and Japan have shown that large welfare gains can be achieved by reshaping current emergency plans as incentive-compatible contracts. We apply tools from the mechanisms design literature to show ways to integrate economic incentives into the management of natural disasters and discuss issues related to the application to seismic event recovery. The focus is on restoring lifeline services such as the water, gas, transportation, and electric power networks. We put forward decisional procedures that an uninformed planner could employ to set repair priorities and help to coordinate lifeline firms in the post-earthquake reconstruction.

Contribution to the geology of Thailand and implications for the geodynamic evolution of Southeast Asia

Abstract The purpose of this study is to unravel the geodynamic evolution of Thailand and, from that, to extend the interpretation to the rest of Southeast Asia. The methodology was based in a first time on fieldwork in Northern Thailand and Southernmost Myanmar, using a multidisciplinary approach, and then on the compilation and re-interpretation, in a plate tectonics point of view, of existing data about the whole Southeast Asia. The main results concern the Nan-Uttaradit suture, the Chiang Mai Volcanic Belt and the proposition of a new location for the Palaeotethys suture. This led to the establishment of a new plate tectonic model for the geodynamic evolution of Southeast Asia, implying the existence new terranes (Orang Laut and the redefinition of Shan-Thai) and the role of the Palaeopacific Ocean in the tectonic development of the area. The model proposed here considers the Palaeotethys suture as located along the Tertiary Mae Yuam Fault, which represents the divide between the Cimmerian Sibumasu terrane and the Indochina-derived Shan-Thai block. The term Shan-Thai, previously used to define the Cimmerian area (when the Palaeotethys suture was thought to represented by the Nan-Uttaradit suture), was redefined here by keeping its geographical location within the Shan States of Myanmar and Central-Northern Thailand, but attributing it an East Asian Origin. Its detachment from Indochina was the result of the Early Permian opening of the Nan basin. The Nan basin closed during the Middle Triassic, before the deposition of Carnian-Norian molasse. The modalities of the closure of the basin imply a first phase of Middle Permian obduction, followed by final eastwards subduction. The Chiang Mai Volcanic Belt consists of scattered basaltic rocks erupted at least during the Viséan in an extensional continental intraplate setting, on the Shan-Thai part of the Indochina block. The Viséan age was established by the dating of limestone stratigraphically overlying the basalts. In several localities of the East Asian Continent, coeval extensional features occur, possibly implying one or more Early Carboniferous extensional events at a regional scale. These events occurred either due to the presence of a mantle plume or to the roll-back of the Palaeopacific Ocean, subducting beneath Indochina and South China, or both. The Palaeopacific Ocean is responsible, during the Early Permian, for the opening of the Song Ma and Poko back-arcs (Vietnam) with the consequent detachment of the Orang Laut Terranes (Eastern Vietnam, West Sumatra, Kalimantan, Palawan, Taiwan). The Late Triassic/Early Jurassic closure of the Eastern Palaeotethys is considered as having taken place by subduction beneath its southern margin (Gondwana), due to the absence of Late Palaeozoic arc magmatism on its northern (Indochinese) margin and the presence of volcanism on the Cimmerian blocks (Mergui, Lhasa). Résumé Le but de cette étude est d'éclaircir l'évolution géodynamique de la Thaïlande et, à partir de cela, d'étendre l'interprétation au reste de l'Asie du Sud-Est. La méthodologie utilisée est basée dans un premier temps sur du travail de terrain en Thaïlande du nord et dans l'extrême sud du Myanmar, en se basant sur une approche pluridisciplinaire. Dans un deuxième temps, la compilation et la réinterprétation de données préexistantes sur l'Asie du Sud-est la été faite, dans une optique basée sur la tectonique des plaques. Les principaux résultats de ce travail concernent la suture de Nan-Uttaradit, la « Chiang Mai Volcanic Belt» et la proposition d'une nouvelle localité pour la suture de la Paléotethys. Ceci a conduit à l'établissement d'un nouveau modèle pour l'évolution géodynamique de l'Asie du Sud-est, impliquant l'existence de nouveaux terranes (Orang Laut et Shan-Thai redéfini) et le rôle joué par le Paléopacifique dans le développement tectonique de la région. Le modèle présenté ici considère que la suture de la Paléotethys est située le long de la faille Tertiaire de Mae Yuam, qui représente la séparation entre le terrain Cimmérien de Sibumasu et le bloc de Shan-Thai, d'origine Indochinoise. Le terme Shan-Thai, anciennement utilise pour définir le bloc Cimmérien (quand la suture de la Paléotethys était considérée être représentée par la suture de Nan-Uttaradit), a été redéfini ici en maintenant sa localisation géographique dans les états Shan du Myanmar et la Thaïlande nord-centrale, mais en lui attribuant une origine Est Asiatique. Son détachement de l'Indochine est le résultat de l'ouverture du basin de Nan au Permien Inférieur. Le basin de Nan s'est fermé pendant le Trias Moyen, avant le dépôt de molasse Carnienne-Norienne. Les modalités de fermeture du basin invoquent une première phase d'obduction au Permien Moyen, suivie par une subduction finale vers l'est. La "Chiang Mai Volcanic Belt" consiste en des basaltes éparpillés qui ont mis en place au moins pendant le Viséen dans un contexte extensif intraplaque continental sur la partie de l'Indochine correspondant au bloc de Shan-Thai. L'âge Viséen a été établi sur la base de la datation de calcaires qui surmontent stratigraphiquement les basaltes. Dans plusieurs localités du continent Est Asiatique, des preuves d'extension plus ou moins contemporaines ont été retrouvées, ce qui implique l'existence d'une ou plusieurs phases d'extension au Carbonifère Inférieur a une échelle régionale. Ces événements sont attribués soit à la présence d'un plume mantellique, ou au rollback du Paléopacifique, qui subductait sous l'Indochine et la Chine Sud, soit les deux. Pendant le Permien inférieur, le Paléopacifique est responsable pour l'ouverture des basins d'arrière arc de Song Ma et Poko (Vietnam), induisant le détachement des Orang Laut Terranes (Est Vietnam, Ouest Sumatra, Kalimantan, Palawan, Taiwan). La fermeture de la Paléotethys Orientale au Trias Supérieur/Jurassique Inférieur est considérée avoir eu lieu par subduction sous sa marge méridionale (Gondwana), à cause de l'absence de magmatisme d'arc sur sa marge nord (Indochinoise) et de la présence de volcanisme sur les blocs Cimmériens de Lhassa et Sibumasu (Mergui). Résumé large public L'histoire géologique de l'Asie du Sud-est depuis environ 430 millions d'années a été déterminée par les collisions successives de plusieurs continents les uns avec les autres. Il y a environ 430 millions d'années, au Silurien, un grand continent appelé Gondwana, a commencé à se «déchirer» sous l'effet des contraintes tectoniques qui le tiraient. Cette extension a provoqué la rupture du continent et l'ouverture d'un grand océan, appelé Paléotethys, éloignant les deux parties désormais séparées. C'est ainsi que le continent Est Asiatique, composé d'une partie de la Chine actuelle, de la Thaïlande, du Myanmar, de Sumatra, du Vietnam et de Bornéo a été entraîné avec le bord (marge) nord de la Paléotethys, qui s'ouvrait petit à petit. Durant le Carbonifère Supérieur, il y a environ 300 millions d'années, le sud du Gondwana subissait une glaciation, comme en témoigne le dépôt de sédiments glaciaires dans les couches de cet âge. Au même moment le continent Est Asiatique se trouvait à des latitudes tropicales ou équatoriales, ce qui permettait le dépôt de calcaires contenant différents fossiles de foraminifères d'eau chaude et de coraux. Durant le Permien Inférieur, il y a environ 295 millions d'années, la Paléotethys Orientale, qui était un relativement vieil océan avec une croûte froide et lourde, se refermait. La croûte océanique a commencé à s'enfoncer, au sud, sous le Gondwana. C'est ce que l'on appelle la subduction. Ainsi, le Gondwana s'est retrouvé en position de plaque supérieure, par rapport à la Paléotethys qui, elle, était en plaque inférieure. La plaque inférieure en subductant a commencé à reculer. Comme elle ne pouvait pas se désolidariser de la plaque supérieure, en reculant elle l'a tirée. C'est le phénomène du «roll-back ». Cette traction a eu pour effet de déchirer une nouvelle fois le Gondwana, ce qui a résulté en la création d'un nouvel Océan, la Neotethys. Cet Océan en s'ouvrant a déplacé une longue bande continentale que l'on appelle les blocs Cimmériens. La Paléotethys était donc en train de se fermer, la Neotethys de s'ouvrir, et entre deux les blocs Cimmériens se rapprochaient du Continent Est Asiatique. Pendant ce temps, le continent Est Asiatique était aussi soumis à des tensions tectoniques. L'Océan Paléopacifique, à l'est de celui-ci, était aussi en train de subducter. Cette subduction, par roll-back, a déchiré le continent en détachant une ligne de microcontinents appelés ici « Orang Laut Terranes », séparés du continent par deux océans d'arrière arc : Song Ma et Poko. Ceux-ci sont composés de Taiwan, Palawan, Bornéo ouest, Vietnam oriental, et la partie occidentale de Sumatra. Un autre Océan s'est ouvert pratiquement au même moment dans le continent Est Asiatique : l'Océan de Nan qui, en s'ouvrant, a détaché un microcontinent appelé Shan-Thai. La fermeture de l'Océan de Nan, il y a environ 230 millions d'années a resolidarisé Shan-Thai et le continent Est Asiatique et la trace de cet événement est aujourd'hui enregistrée dans la suture (la cicatrice de l'Océan) de Nan-Uttaradit. La cause de l'ouverture de l'Océan de Nan peut soit être due à la subduction du Paléopacifique, soit aux fait que la subduction de la Paléotethys tirait le continent Est Asiatique par le phénomène du « slab-pull », soit aux deux. La subduction du Paléopacifique avait déjà crée de l'extension dans le continent Est Asiatique durant le Carbonifère Inférieur (il y a environ 340-350 millions d'années) en créant des bassins et du volcanisme, aujourd'hui enregistré en différents endroits du continent, dont la ceinture volcanique de Chiang Mai, étudiée ici. A la fin du Trias, la Paléotethys se refermait complètement, et le bloc Cimmérien de Sibumasu entrait en collision avec le continent Est Asiatique. Comme c'est souvent le cas avec les grands océans, il n'y a pas de suture proprement dite, avec des fragments de croûte océanique, pour témoigner de cet évènement. Celui-ci est visible grâce à la différence entre les sédiments du Carbonifère Supérieur et du Permieñ Inférieur de chaque domaine : dans le domaine Cimmérien ils sont de type glaciaire alors que dans le continent Est Asiatique ils témoignent d'un climat tropical. Les océans de Song Ma et Poko se sont aussi refermés au Trias, mais eux ont laissé des sutures visibles

Els isòtops radiogènics(Sr i Nd) en diferents contextes geodinàmics: Illes Canaries i Vesuvi. Preparació i anàlisi de mostres mitjançant la tècnica analítica TIMS

Projecte de recerca elaborat a partir d’una estada l’ Osservatorio Vesuviano (Nàpols, Italia) entre novembre del 2006 i març del 2007. Un dels objectius principals de l’estada ha estat conèixer la tècnica analítica Thermal Ionisation Mass Spectrometry (TIMS ) per l’anàlisi d’isòtops radiogènics (Sr i Nd). Aquesta estada ha permès aprendre tant la part de preparació de les mostres, com la part d’utilització i programació de l’instrument. Inicialment en el projecte es va programar l’anàlisi dels isòtops radiogènics en laves i xenòlits de l’illa de Gran Canaria (Illes Canàries) amb l’objectiu de modelar geoquímicament el mantell terrestre sota les illes Canàries. Finalment, i a part de les mostres inicials de Gran Canaria, es van incloure mostres del volcà Vesuvi per tal de concloure un projecte iniciat el 2003 amb el Professor Giovanni Orsi i la Professora Lucia Civetta. L’estudi dels isòtops radiogènics en contextes geodinàmics tant diferents ha permès comparar la variació dels isòtops radiogènics de Sr i Nd que existeix entre volcanisme d’ intraplaca (Illes Canàries) i volcanisme en zones convergents (Vesuvi).

Late Cretaceous and Paleogene Radiolaria from the Nicoya Peninsula, Costa Rica: a tectonostratigraphic application

Detailed field mapping and paleontological dating in the central and southeastern Nicoya Peninsula has revealed Late Cretaceous and Paleogene radiolarian-bearing siliceous mudstones. These rocks belong to two terranes (Matambfi and Manzanillo) that are partially contemporaneous with the Nicoya Complex, but are genetically different. While the Nicoya Complex is formed exclusively by intraplate igneous rocks with associated radiolarites, the studied sections include variable amounts of are-derived volcanic and terrigenous materials. These fore-arc terranes include mafic to intermediate volcaniclastics and associated pelagic and hemipelagic rocks rich in biogenic silica. Radiolarian preservation in these sediments is often enhanced by the presence of silica-saturated volcanic tuffs and debris. Seven out of 29 samples from different outcrops yielded relatively well-preserved radiolarian faunas. In total, 60 species belonging to 34 genera were present in these faunas, ranging in age from middle Turonian-Santonian to late Thanetian-Ypresian.

Tropical cyclones as a critical phenomenon

It has been proposed that the number of tropical cyclones as a function of the energy they release is a decreasing power-law function, up to a characteristic energy cutoff determined by the spatial size of the ocean basin in which the storm occurs. This means that no characteristic scale exists for the energy of tropical cyclones, except for the finite-size effects induced by the boundaries of the basins. This has important implications for the physics of tropical cyclones. We discuss up to what point tropical cyclones are related to critical phenomena (in the same way as earthquakes, rainfall, etc.), providing a consistent picture of the energy balance in the system. Moreover, this perspective allows one to visualize more clearly the effects of global warming on tropical-cyclone occurrence.

Probability distribution of the radionuclide half-lives

Power law distributions, a well-known model in the theory of real random variables, characterize a wide variety of natural and man made phenomena. The intensity of earthquakes, the word frequencies, the solar ares and the sizes of power outages are distributed according to a power law distribution. Recently, given the usage of power laws in the scientific community, several articles have been published criticizing the statistical methods used to estimate the power law behaviour and establishing new techniques to their estimation with proven reliability. The main object of the present study is to go in deep understanding of this kind of distribution and its analysis, and introduce the half-lives of the radioactive isotopes as a new candidate in the nature following a power law distribution, as well as a \canonical laboratory" to test statistical methods appropriate for long-tailed distributions.

Semiactive backstepping control for vibration attenuation in structures equipped with magnetorheological actuatorscat

This paper deals with the problem of semiactive vibration control of civil engineering structures subject to unknown external disturbances (for example, earthquakes, winds, etc.). Two kinds of semiactive controllers are proposed based on the backstepping control technique. The experimental setup used is a 6-story test structure equipped with shear-mode semiactive magnetorheological dampers being installed in the Washington University Structural Control and Earthquake Engineering Laboratory (WUSCEEL). The experimental results obtained have verified the effectiveness of the proposed control algorithms

Improved earthquake response via simulation and integrated space- and ground-based technologies: the TREMOR proposal

Earthquakes occurring around the world each year cause thousands ofdeaths, millions of dollars in damage to infrastructure, and incalculablehuman suffering. In recent years, satellite technology has been asignificant boon to response efforts following an earthquake and itsafter-effects by providing mobile communications between response teamsand remote sensing of damaged areas to disaster management organizations.In 2007, an international team of students and professionals assembledduring theInternational Space University’s Summer Session Program in Beijing, Chinato examine how satellite and ground-based technology could be betterintegrated to provide an optimised response in the event of an earthquake.The resulting Technology Resources for Earthquake MOnitoring and Response(TREMOR) proposal describes an integrative prototype response system thatwill implement mobile satellite communication hubs providing telephone anddata links between response teams, onsite telemedicine consultation foremergency first-responders, and satellite navigation systems that willlocate and track emergency vehicles and guide search-and-rescue crews. Aprototype earthquake simulation system is also proposed, integratinghistorical data, earthquake precursor data, and local geomatics andinfrastructure information to predict the damage that could occur in theevent of an earthquake. The backbone of these proposals is a comprehensiveeducation and training program to help individuals, communities andgovernments prepare in advance. The TREMOR team recommends thecoordination of these efforts through a centralised, non-governmentalorganization.

High-resolution seismic images of potentially seismogenic structures beneath the northwest Canterbury Plains, New Zealand

The transpressional boundary between the Australian and Pacific plates in the central South Island of New Zealand comprises the Alpine Fault and a broad region of distributed strain concentrated in the Southern Alps but encompassing regions further to the east, including the northwest Canterbury Plains. Low to moderate levels of seismicity (e. g., 2 > M 5 events since 1974 and 2 > M 4.0 in 2009) and Holocene sediments offset or disrupted along rare exposed active fault segments are evidence for ongoing tectonism in the northwest plains, the surface topography of which is remarkably flat and even. Because the geology underlying the late Quaternary alluvial fan deposits that carpet most of the plains is not established, the detailed tectonic evolution of this region and the potential for larger earthquakes is only poorly understood. To address these issues, we have processed and interpreted high-resolution (2.5 m subsurface sampling interval) seismic data acquired along lines strategically located relative to extensive rock exposures to the north, west, and southwest and rare exposures to the east. Geological information provided by these rock exposures offer important constraints on the interpretation of the seismic data. The processed seismic reflection sections image a variably thick layer of generally undisturbed younger (i.e., < 24 ka) Quaternary alluvial sediments unconformably overlying an older (> 59 ka) Quaternary sedimentary sequence that shows evidence of moderate faulting and folding during and subsequent to deposition. These Quaternary units are in unconformable contact with Late Cretaceous-Tertiary interbedded sedimentary and volcanic rocks that are highly faulted, folded, and tilted. The lowest imaged unit is largely reflection-free Permian Triassic basement rocks. Quaternary-age deformation has affected all the rocks underlying the younger alluvial sediments, and there is evidence for ongoing deformation. Eight primary and numerous secondary faults as well as a major anticlinal fold are revealed on the seismic sections. Folded sedimentary and volcanic units are observed in the hanging walls and footwalls of most faults. Five of the primary faults represent plausible extensions of mapped faults, three of which are active. The major anticlinal fold is the probable continuation of known active structure. A magnitude 7.1 earthquake occurred on 4 September 2010 near the southeastern edge of our study area. This predominantly right-lateral strike-slip event and numerous aftershocks (ten with magnitudes >= 5 within one week of the main event) highlight the primary message of our paper: that the generally flat and topographically featureless Canterbury Plains is underlain by a network of active faults that have the potential to generate significant earthquakes.

Global mass wasting during the Middle Ordovician: Meteoritic trigger or plate-tectonic environment ?

Mass wasting at continental margins on a global scale during the Middle Ordovician has recently been related to high meteorite influx. Although a high meteorite influx during the Ordovician should not be neglected, we challenge the idea that mass wasting was mainly produced by meteorite impacts over a period of almost 10 Ma. Having strong arguments against the impact-related hypothesis, we propose an alternative explanation, which is based on a re-evaluation of the mass wasting sites, considering their plate-tectonic distribution and the global sea level curve. A striking and important feature is the distribution of most of the mass wasting sites along continental margins characterised by periods of magmatism, terrane accretion and continental or back-arc rifting, respectively, related to subduction of oceanic lithosphere. Such processes are commonly connected with seismic activity causing earthquakes, which can cause downslope movement of sediment and rock. Considering all that, it seems more likely that most of this mass wasting was triggered by earthquakes related to plate-tectonic processes, which caused destabilisation of continental margins resulting in megabreccias and debris flows. Moreover, the period of mass wasting coincides with sea level drops during global sea level lowstand. In some cases, sea level drops can release pore-water overpressure reducing sediment strength and hence promoting instability of sediment at continental margins. Reduced pore-water overpressure can also destabilise gas hydrate-bearing sediment, causing slope failure, and thus resulting in submarine mass wasting. Overall, the global mass wasting during the Middle Ordovician does not need meteoritic trigger. (C) 2010 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Earthquake impacts in old-growth Nothofagus forests in New Zealand

Six stands located on different land forms in mixed old-growth Nothofagus forests in the Matiri Valley (northwest of South Island. New Zealand) were sampled to examine the effects of two recent large earthquakes on tree establishment and tree-ring growth, and how these varied across land forms. 50 trees were cor ed in each stand to determine age structure and the cores were cross-dated to precisely date unusual periods of radial growth. The 1968 earthquake (M = 7.1, epicentre 35 km from the study area) had no discernible impact on the sampled stands. The impact of the 1929 earthquake (M = 7.7, epicentre 20 kin from the study area) varied between stands, depending on whether or not they had been damaged by soil or rock movement. In all stands, the age structures showed a pulse of N. fusca establishment following the 1929 earthquake, with this species dominating establishment in large gaps created by landslides. Smaller gaps, created by branch or tree death, were closed by both N. fusca and N. menziesii. The long period of releases (1929-1945) indicates that direct earthquake damage was not the only cause of tree death, and that many trees died subsequently most likely of pathogen attack or a drought in the early 1930s. The impacts of the 1929 earthquake are compared to a storm in 1905 and a drought in 1974-1978 which also affected forests in the region. Our results confirm that earthquakes are an important factor driving forest dynamics in this tectonically active region, and that the diversity of earthquake impacts is a major source of heterogeneity in forest structure and regeneration.

Estudo do Ruído Sísmico no Arquipélago de Cabo Verde

Traditionally the study of Earth's internal structure has been based on analysis of seismic waves recorded during the occurrence of earthquakes. Recently, some researchers have shown to be possible to use ambient seismic noise (generally generated by ocean storms) to obtain dispersion curves with satisfactory results. Moreover, the use of ambient seismic noise measurement has advantages because they are independent of the earthquake-station geometry. This study aims to determine the dispersion curves of Rayleigh waves from the analysis of ambient seismic noise records, obtained in Cape Verde archipelago, whose origin and structure has attracted interest from several researchers. Analyzing the data collected between November 2007 and September 2008, Green's functions were determined. The analysis of these functions allowed to construct energy diagrams and to measure dispersion curves of group velocities between pairs of stations.

DIGITAL LIBRARY FOR DIGITAL DIVIDE AND ENVIRONMENT OF SCARCE ACCESS TO PRINTED MATERIALS: THE CASE OF UNIVERSITY JEAN PIAGET OF CAPE VERDE

With the failure of the traditional mechanisms of distributing bibliographic materials into developing countries, digital libraries show up as a strong alternative in accomplishing such job, despite the challenges of the digital divide. This paper discusses the challenges of building a digital library (DL) in a developing country. The case of Cape Verde as a digital divide country is analyzed, in terms of current digital library usage and its potentiality for fighting the difficulties in accessing bibliographic resources in the country. The paper also introduces an undergoing project of building a digital library at the University Jean Piaget of Cape Verde.