Volcanic tsunami: a review of source mechanisms, past events and hazards in Southeast Asia (Indonesia, Philippines, Papua New Guinea)     

Raphaël Paris  Adam D. Switzer  Marina Belousova  Alexander Belousov  Budianto Ontowirjo  Patrick L. Whelley  Martina Ulvrova 《Natural Hazards》2014,70(1):447-470

Southeast Asia has had both volcanic tsunamis and possesses some of the most densely populated, economically important and rapidly developing coastlines in the world. This contribution provides a review of volcanic tsunami hazard in Southeast Asia. Source mechanisms of tsunami related to eruptive and gravitational processes are presented, together with a history of past events in the region. A review of available data shows that many volcanoes are potentially tsunamigenic and present often neglected hazard to the rapidly developing coasts of the region. We highlight crucial volcanic provinces in Indonesia, the Philippines and Papua New Guinea and propose strategies for facing future events.  相似文献   

The use of radar observations of Near-Earth Asteroids in the determination of the dynamical equinox     

Eleonora I. Yagudina 《Celestial Mechanics and Dynamical Astronomy》2001,80(3-4):195-203

Near-Earth Asteroids (NEAs) are Solar system special class objects attracting the attention of astronomical community especially during several of the last decades. To some extent the NEAs have an advantage over the minor planets of the main belt: due to close and regular approaches to the Earth the radar observations of NEAs can be obtained for the greater number of objects than for those of the main belt of the minor planets. In this paper the use of all available radar observations together with optical ones resulting in the combined data analysis solution is discussed for different problems such as the asteroid orbits and catalog orientation parameters determination. In particular the problem of the motion of the dynamical equinox in the Hipparcos reference system is considered. About 13000 radar and optical observations of 24 NEAs and main belt minor planets have been used to obtain the precise asteroid orbits, FK5 catalogue orientation parameters and the motion of the dynamical equinox from 1750 till 2000 in the Hipparcos system.  相似文献   

Ice-rich terrain in Gusev Crater, Mars?     

Tracy K.P. Gregg  Jason P. Briner  Kristen N. Paris   《Icarus》2007,192(2):348-360

The morphology of materials on the floor of Gusev Crater (14° S, 175° W), Mars, imply a history of volcanism and subsequent removal of an ice-rich deposit. Fluid lava flows observed in the western portion of Gusev Crater paradoxically terminate in a steep, thick (<60 m) flow front adjacent to hummocky terrain. The hummocky terrain is morphologically similar to deglaciated terrain on Earth, generated when glacial debris are left behind after the glacier has retreated. We propose the following scenario for the floor of Gusev Crater. First, ice-rich material was deposited adjacent to Thira Crater. Second, fluid lavas were emplaced and ponded against the ice-rich deposits. At some later time, the ice within the deposit sublimated, leaving hummocky terrain. Current age estimates for the Gusev flows are Hesperian, suggesting that the ice removal occurred in the upper Hesperian or more recently. If this hypothesis is correct, quench features (glassy rinds, columnar jointing) should be observed at the lava flow margin; the hummocky deposit should be poorly sorted, angular debris.  相似文献   

Boron isotope ratios of surface waters in Guadeloupe,Lesser Antilles     

Pascale Louvat  Jérôme Gaillardet  Guillaume Paris  Céline Dessert 《Applied Geochemistry》2011

Large variations are reported in the B concentrations and isotopic ratios of river and thermal spring waters in Guadeloupe, Lesser Antilles. Rivers have δ¹¹B values around 40‰ and B concentrations lower than 30 μg/L, while thermal springs have δ¹¹B of 8–15‰ and B concentrations of 250–1000 μg/L. River samples strongly impacted by hydrothermal inputs have intermediate δ¹¹B and B contents. None of these surface water samples have δ¹¹B comparable to the local unweathered volcanic rocks (around 0‰), implying that a huge isotopic fractionation of 40‰ takes place during rock weathering, which could be explained by preferential incorporation of ¹⁰B during secondary mineral formation and adsorption on clays, during rock weathering or in the soils. The soil-vegetation B cycle could also be a cause for such a fractionation. Atmospheric B with δ¹¹B of 45‰ represents 25–95% of the river B content. The variety of the thermal spring chemical composition renders the understanding of B behavior in Guadeloupe hydrothermal system quite difficult. Complementary geochemical tracers would be helpful.  相似文献   

Impacts of landscape fragmentation on simulated precipitation fields in the Amazonian sub-basin of Ji-Paraná using the Eta model     

Daniel Andres Rodriguez  Sin Chan Chou  Javier Tomasella  Eleonora M. C. Demaria 《Theoretical and Applied Climatology》2014,115(1-2):121-140

Numerical studies on impacts of landscape fragmentation due to land use and land cover change (LUCC) on precipitation fields over the Ji-Paraná basin in the Amazon region are carried out using atmospheric Eta model. Experiments consider historical data about LUCC over the basin from 1978 to 2000 and compare simulations under LUCC conditions with simulations under pristine conditions. In agreement with previous observational studies, model results do not show statistically significant impacts on precipitation in the region. Results indicate that variability in precipitation in this region is mainly controlled by large-scale atmospheric characteristics and soil moisture conditions. However, some limitations are identified in the model simulations, mainly associated to the diurnal cycle of precipitation.  相似文献   

Coupling eruption and tsunami records: the Krakatau 1883 case study,Indonesia     

Raphaël Paris  Patrick Wassmer  Franck Lavigne  Alexander Belousov  Marina Belousova  Yan Iskandarsyah  Mhammed Benbakkar  Budianto Ontowirjo  Nelly Mazzoni 《Bulletin of Volcanology》2014,76(4):1-23

The well-documented 1883 eruption of Krakatau volcano (Indonesia) offers an opportunity to couple the eruption’s history with the tsunami record. The aim of this paper is not to re-analyse the scenario for the 1883 eruption but to demonstrate that the study of tsunami deposits provides information for reconstructing past eruptions. Indeed, though the characteristics of volcanogenic tsunami deposits are similar to those of other tsunami deposits, they may include juvenile material (e.g. fresh pumice) or be interbedded with distal pyroclastic deposits (ash fall, surges), due to their simultaneity with the eruption. Five kinds of sedimentary and volcanic facies related to the 1883 events were identified along the coasts of Java and Sumatra: (1) bioclastic tsunami sands and (2) pumiceous tsunami sands, deposited respectively before and during the Plinian phase (26–27 August); (3) rounded pumice lapilli reworked by tsunami; (4) pumiceous ash fall deposits and (5) pyroclastic surge deposits (only in Sumatra). The stratigraphic record on the coasts of Java and Sumatra, which agrees particularly well with observations of the 1883 events, is tentatively linked to the proximal stratigraphy of the eruption.  相似文献   

Aerosol Measurements in the Atmospheric Surface Layer at L’Aquila,Italy: Focus on Biogenic Primary Particles     

Giovanni Pitari  Eleonora Coppari  Natalia De Luca  Piero Di Carlo  Loretta Pace 《Pure and Applied Geophysics》2014,171(9):2425-2441

Two year measurements of aerosol concentration and size distribution (0.25 μm < d < 30 μm) in the atmospheric surface layer, collected in L’Aquila (Italy) with an optical particle counter, are reported and analysed for the different modes of the particle size distribution. A different seasonal behaviour is shown for fine mode aerosols (largely produced by anthropogenic combustion), coarse mode and large-sized aerosols, whose abundance is regulated not only by anthropogenic local production, but also by remote natural sources (via large scale atmospheric transport) and by local sources of primary biogenic aerosols. The observed total abundance of large particles with diameter larger than 10 μm is compared with a statistical counting of primary biogenic particles, made with an independent technique. Results of these two observational approaches are analysed and compared to each other, with the help of a box model driven by observed meteorological parameters and validated with measurements of fine and coarse mode aerosols and of an atmospheric primary pollutant of anthropogenic origin (NO_x). Except in winter months, primary biogenic particles in the L’Aquila measurement site are shown to dominate the atmospheric boundary layer population of large aerosol particles with diameter larger than 10 μm (about 80 % of the total during summer months), with a pronounced seasonal cycle, contrary to fine mode aerosols of anthropogenic origin. In order to explain these findings, the main mechanisms controlling the abundance and variability of particulate matter tracers in the atmospheric surface layer are analysed with the numerical box-model.  相似文献   

Distinction between six- and fourfold coordinated silicon in SiO2 polymorphs via electron loss near edge structure (ELNES) spectroscopy     

T. Sharp  Z. Wu  F. Seifert  B. Poe  M. Doerr  E. Paris 《Physics and Chemistry of Minerals》1996,23(1):17-24

Si K-, L- and O K-edge ELNES spectra of natural α-quartz and synthetic coesite on one side and synthetic stishovite on the other show characteristic differences that can be related, by comparison with multiple-scattering (MS) calculations, to the fourfold vs. sixfold coordination of Si in these polymorphs of SiO₂. It is shown by MS calculations on large clusters that the outer shells contribute relatively little to the overall topologies of the spectra. Therefore, distinction between fourfold- and sixfold-coordinated Si is possible even on a nm scale and probably also in amorphous substances.  相似文献   

The local structure of Ca-Na pyroxenes. II. XANES studies at the Mg and Al K edges     

A. Mottana  T. Murata  A. Marcelli  Z. Y. Wu  G. Cibin  E. Paris  G. Giuli 《Physics and Chemistry of Minerals》1999,27(1):20-33

X-ray absorption spectra at the Mg and Al K edges have been recorded using synchrotron radiation on synthetic end member diopside (Di) and jadeite (Jd) and on a series of natural Fe-poor Ca-Na clinopyroxenes compositionally straddling the Jd-Di join. The spectra of C2/c end members and intermediate members of the solid solution series (C-omphacites) are different from those of the intermediate members having P2/n symmetry (P-omphacites). Differences can be interpreted and explained by comparing the experimental spectra with theoretical spectra calculated via the full multiple-scattering formalism, starting from the atomic positional parameters determined by single-crystal X-ray diffraction structure refinement on the same samples. Atomic clusters with at least 89 atoms, extending to more than 0.60 nm away from the Mg or Al absorbers, are needed to reproduce the experimental spectra. This shows that in the clinopyroxene systems XANES detects medium- rather than short-range order-disorder relationships. Theoretical spectra match the experimental ones well for all features in the regions from 16 to 60 eV above threshold. Experimental near-edge features in the first 16 eV are also reproduced, albeit less accurately. Certain near-edge features of C-omphacites reflect the octahedral arrangement of the back-scattering six O atoms nearest neighbours of the probed atom (Mg or Al) located at site M1 of the crystal structure, thus being indicators of short-range order. Others arise again from medium-range order. P-omphacites show more complicated spectra than C-omphacites. Their additional features reflect the increased complexity of the structure and the greater local disorder around the probed atom induced by the two alternative M1, M11 configurations of the six O atoms forming the first coordination shells. Mg and Al are confirmed to be preferentially partitioned in the M1 and M11 site of the P-omphacite crystal structure, however with a certain degree of local disorder. The relative heights of certain prominent features are directly related to sample composition in terms of Di:Jd ratio in the Al K-edge spectra, whereas they show abrupt variations in the Mg K-edge spectra. They demonstrate that XANES is directly related to composition and may be used to distinguish C- from P-omphacites. Received: 24 November 1998 / Revised, accepted: 10 June 1999  相似文献   

Some major concepts of metallogeny     

Laboratoire de Géologie Appliquée  Université de Paris 《Mineralium Deposita》1973,8(3):237-258

These notes, which summarize part of over ten years of laboratory work, aim to clarify and inter-relate three fundamental concepts of current Metallogeny: consanguinity, heritage, province. — 1. The concept of consanguinity: its criteria, limits and graduations, are first presented; 2. They are illustrated by the analysis of a complex example: the lead-zinc mineralisations in Trias around the Cévennes (South of the French Massif Central); 3. The likelihood of consanguinity for various strata-bound mineralisations, particularly misappreciated and misinterpreted, is then shown: — tungsten in the Cévennes — gold at Passagem (Brazil), about which microstructural and geochemical arguments are especially employed — cobalt at Bou Azzer (Marocco); 4. From consanguinity in a sedimentary environment, the authors turn to the crustal phenomena cycle, during which the heritages of the cations succeed one another. Examples of heritages, linked with sedimentation-volcanism: Sierra de Carthagena (Spain) — metamorphism — granitisation, are rapidly examined or referred to in literature. Particular attention has been paid to heritage by secretion, illustrated by the antimony lodes of the French Massif Central. Consequently, it may be understood how the successive heritages involve geochemical permanences and determine the geochemical provinces going back to ancient times in which the mineral provinces were built up. 5. In a last section the transformist guide line is compared with other concepts and tools of Metallogeny: lineaments and isotopic ratios. — In conclusion, the intra-crustal heritages still remain under-estimated and badly deciphered and are not sufficiently taken into consideration in mineral exploration.

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Zusammenfassung Diese Veröffentlichung, die einen Teil der während eines Jahrzehnts in einem Laboratorium ausgeführten Arbeiten kurz behandelt, hat die Aufgabe, drei Grundbegriffe der gegenwärtigen Metallogenese klarzustellen und miteinander zu verknüpfen: Familiarität (Verwandtschaft), Vererbung und Provinz. — 1. Der Begriff der Verwandtschaft sowie seine Kriterien, Grenzen und Nuancen werden zuerst auseinandergesetzt. 2. Dann wird dieser Begriff anhand der Analyse eines komplizierten Beispiels veranschaulicht, und zwar der Blei-Zink-Mineralisationen in der Trias am Rand der Cevennen, im Süden des französischen Zentralmassivs gelegen; 3. Anschließend wird die Wahrscheinlichkeit der Verwandtschaft für verschiedene schichtgebundene, besonders verkannte und falsch interpretierte Mineralisationen aufgezeigt. Es handelt sich einerseits um das Wolfram der Cevennen sowie das Kobalt von Bou Azzer (Marokko) und andererseits um das Gold von Passagem (Brasilien), zu dessen Erklärung insbesonders mikrostrukturelle und geochemische Argumente herangezogen werden; 4. So gelangt man in den Kreislauf der Krustalerscheinungen, währenddessen Vererbungen von Kationen aufeinanderfolgen. Beispiele von Vererbungen, die an Sedimentation, Vulkanismus (Sierra von Cartagena, Spanien), Metamorphose und Granitisierung gebunden sind, werden kurz untersucht oder anhand von Literaturangaben erwähnt. Besondere Erwähnung verdient die Sekretionsvererbung, die am Beispiel der Antimonerzgänge des französischen Zentralmassivs veranschaulicht wird. Somit wird verständlich, wie die aufeinanderfolgenden Vererbungen geochemische Beständigkeiten bedingen. Sie bestimmen ebenfalls geochemische, auf das hohe Altertum zurückgehende Provinzen, auf denen sich die Mineralprovinzen aufbauen; 5. Zum Schluss wird diese transformistische Leitrichtung mit anderen Konzepten und Arbeitsmitteln der Metallogenese verglichen: den Lineamenten und Isotopenverhältnissen. — Es wird der Schluß gefolgert, daß die intrakrustalen Vererbungen immer noch unterschätzt, schlecht entziffert und bei der Lagerstättenforschung ungenügend in Betracht gezogen werden.

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Illustrated by Examples

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Laboratory associated with the C.N.R.S. (n^o 65). Contributors to this paper: P. Routhier (former Director of the Laboratory at present Director in the B.R.G.M.) and P. Brouder, R. Fleischer, (at present in the Penarroya C⁰), J. C. Macquar, Melle M. J. Pavillon, G. Roger and H. Rouvier.  相似文献