The Bayesian probabilistic prediction of strong earthquakes in the Hellenic arc     

Sergio G. Ferraes 《Tectonophysics》1985,111(3-4)

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Inelastic seismic analysis of a building structure designed by argentine codes     

Victorio E. Sonzogni  Alberto Cardona  Sergio R. Idelsohn 《地震工程与结构动力学》1984,12(6):721-736

A reinforced concrete frame-wall structure of a building designed in accordance to standard practice in Argentina was analysed by the procedures prescribed by current Argentine Codes. In addition, the inelastic step-by-step response of the structure to design spectrum-compatible accelerograms was studied by means of a special element for inelastic dynamic analysis of reinforced concrete frames. Results obtained by the different methods of analysis are presented.  相似文献   

Provenance, environmental and paleogeographic controls on sandstone composition in an incised-valley system: the Eocene La Meseta Formation, Seymour Island, Antarctica     

Sergio A. Marenssi  Laura I. Net  Sergio N. Santillana 《Sedimentary Geology》2002,150(3-4):301-321

The Eocene La Meseta Formation is the youngest exposed unit of the back-arc James Ross Basin, Antarctic Peninsula, cropping out in Seymour (Marambio) Island. The formation comprises 720 m of clastic sedimentary rocks of deltaic, estuarine and shallow marine origin. It was subdivided into six unconformity-based units (Valle de Las Focas, Acantilados, Campamento, Cucullaea I, Cucullaea II and Submeseta Allomembers) grouped into three main facies associations. Facies association I represents valley-confined deposition in a progradational/aggradational tide-dominated and wave-influenced delta front/delta plain environment. Facies association II includes tidal channels, mixed tidal flats, tidal inlets and deltas, washover and beach environments. Facies association III represents nonconfined tide- and storm-influenced nearshore environments. La Meseta Formation sandstones are quartzofeldspathic with some hybrid arenites (glauconite and carbonate bioclasts-rich). Sandstone detrital modes are subdivided into two distinctive petrofacies: the low quartz petrofacies (petrofacies I, Q<55% and L>12%), interpreted to retain the original provenance signal, and the high quartz petrofacies (petrofacies II, Q>55% and L<12%), representing the reworking product of the former after selective elimination of the more labile components. Petrofacies I sandstone framework grains were mainly derived from a dissected magmatic arc and an associated metamorphic belt. Textural evidence for recycling of some grains (e.g. garnet) from older sedimentary units during valley incision is not conclusive. Changes in the relative participation of source areas during the evolution of the incised-valley system are evaluated from the relative proportions of lithic fragments and monomineralic clasts derived from each rock type. Two lithic assemblages were recognized. The mixed lithic assemblage (Rv/Rm+Rp<1.4) shows participation of all rock types; it represented valley-confined environments, either during the initial stage of valley development, or after main episodes of incision. The volcanic lithic assemblage (Rv/Rm+Rp>1.4) is clearly dominated by volcanic-derived clasts; it developed at times of high sea level and/or during later stages of the valley fill, when an “energy fence” at the shoreline prevented delivery of sediment from the Antarctic Peninsula, thus enhancing the relative participation of local volcanic sources.  相似文献   

Reply to Discussion on "Giant versus small porphyry copper deposits of Cenozoic age in northern Chile: adakitic versus normal calc-alkaline magmatism" by Oyarzun R,Márquez A,Lillo J,López I,Rivera S (Mineralium Deposita 36:794–798, 2001)     

Roberto Oyarzun  Alvaro Márquez  Javier Lillo  Ivan López  Sergio Rivera 《Mineralium Deposita》2002,37(8):795-799

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Comment: Tephrochronological dating of varved interglacial lake deposits from Piànico‐Sèllere (Southern Alps,Italy) to around 400 ka. Achim Brauer,Sabine Wulf,Clara Mangili and Andrea Moscariello Journal of Quaternary Science 22: 85–96     

Daniele L. Pinti  Virgile Rouchon  Xavier Quidelleur  Pierre‐Yves Gillot  Sergio Chiesa  Cesare Ravazzi 《第四纪科学杂志》2007,22(4):411-414

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How Does Large Flaring Activity from the Same Active Region Produce Oppositely Directed Magnetic Clouds?     

Louise K. Harra  Nancy U. Crooker  Cristina H. Mandrini  Lidia van Driel-Gesztelyi  Sergio Dasso  Jingxiu Wang  Heather Elliott  Gemma Attrill  Bernard V. Jackson  Mario M. Bisi 《Solar physics》2007,244(1-2):95-114

We describe the interplanetary coronal mass ejections (ICMEs) that occurred as a result of a series of solar flares and eruptions from 4 to 8 November 2004. Two ICMEs/magnetic clouds occurring from these events had opposite magnetic orientations. This was despite the fact that the major flares related to these events occurred within the same active region that maintained the same magnetic configuration. The solar events include a wide array of activities: flares, trans-equatorial coronal loop disappearance and reformation, trans-equatorial filament eruption, and coronal hole interaction. The first major ICME/magnetic cloud was predominantly related to the active region 10696 eruption. The second major ICME/magnetic cloud was found to be consistent with the magnetic orientation of an erupting trans-equatorial filament or else a rotation of 160° of a flux rope in the active region. We discuss these possibilities and emphasize the importance of understanding the magnetic evolution of the solar source region before we can begin to predict geoeffective events with any accuracy.  相似文献   

3D soft-sediment deformation structures: evidence for Quaternary seismicity in the Madrid basin, Spain     

Pablo G. Silva  Juan C. Cañaveras  Sergio Sanchez-Moral  Javier Lario  Enrique Sanz 《地学学报》1997,9(5-6):208-212

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North Atlantic oscillation control of droughts in north-east Spain: evaluation since 1600 a.d.     

Sergio M. Vicente-Serrano  José M. Cuadrat 《Climatic change》2007,85(3-4):357-379

This paper analyses the role played by the North Atlantic Oscillation (NAO) in the creation of drought conditions in a semi-arid region of north-east Spain (the middle Ebro valley), from 1600 to the year 2000. The study used documents from ecclesiastical archives for the seventeenth, eighteenth and nineteenth centuries. For the twentieth century, instrumental precipitation records were used as well. A December–August drought index from 1600 to 1900 was compiled from the historical documentary sources (rogation ceremonies). The index was validated by means of precipitation records between 1858 and 1900 and independent precipitation data from 1600 reconstructed by means of dendrochronological records. Using instrumental data a drought index was also calculated (Standardized Precipitation Index, SPI) for the 1958–2000 period. We found that the NAO was important in explaining the droughts identified in the study area from documents and instrumental data. Positive values of the winter NAO index are prone to cause droughts in the middle Ebro valley. This finding has been verified since 1600 by means of two independent reconstructions of the winter NAO index. The same behaviour has been observed during the nineteenth and twentieth centuries by means of instrumental records. The climatic and geographic factors that explain the high influence of North Atlantic Oscillation on droughts in this region are discussed in depth.  相似文献   

Giant versus small porphyry copper deposits of Cenozoic age in northern Chile: adakitic versus normal calc-alkaline magmatism   总被引：63，自引：0，他引：63  

Roberto Oyarzun  Alvaro Márquez  Javier Lillo  Ivan López  Sergio Rivera 《Mineralium Deposita》2001,36(8):794-798

Cenozoic magmatic activity in northern Chile led to the formation of two contrasting porphyry copper belts: (1) a Paleocene-Early Eocene belt comprising small porphyry copper deposits (e.g., Lomas Bayas) of normal calc-alkaline affinity; and (2) a Late Eocene-Early Oligocene belt hosting huge porphyry copper deposits (e.g., Chuquicamata) of adakitic affinity. Although the first belt comprises both volcanic and plutonic rocks (andesitic-basaltic and rhyolitic lavas and tuffs, and associated sub-volcanic porphyries and felsic stocks), the latter only includes intrusions (mostly granodioritic types, including porphyry copper deposits). We suggest that the Late Eocene-Early Oligocene belt formed when fast and oblique convergence between the South America and Farallon plates led to flat subduction and direct melting of the subducting plate, hence giving rise to plutonic rocks of adakitic affinity. The absence of volcanism, under prevailing compressional conditions, prevented the escape of SO₂ from the adakitic, sulfur-rich, highly oxidized magmas ("closed porphyry system"), which allowed formation of huge mineral deposits. On the contrary, coeval volcanic activity during formation of the Paleocene-Early Eocene calc-alkaline porphyries allowed development of "open systems", hence to outgassing, and therefore, to small mineral deposits.  相似文献   

Ammonia observations of the nearby molecular cloud MBM 12     

José F. Gómez  Joaquín Trapero  Sergio Pascual  Nimesh Patel  Carmen Morales  José M. Torrelles 《Monthly notices of the Royal Astronomical Society》2000,314(4):743-746

We present NH₃(1,1) and (2,2) observations of MBM 12, the closest known molecular cloud (65-pc distance), aimed at finding evidence for on-going star formation processes. No local temperature (with a T _rot upper limit of 12 K) or linewidth enhancement is found, which suggests that the area of the cloud that we have mapped (15-arcmin size) is not currently forming stars. Therefore this nearby 'starless' molecular gas region is an ideal laboratory to study the physical conditions preceding new star formation.
A radio continuum source has been found in Very Large Array archive data, close to but outside the NH₃ emission. This source is likely to be a background object.  相似文献