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Louise Wedderkopp Bjerrum Kuvvet Atakan Mathilde Bøttger Sørensen 《Bulletin of Earthquake Engineering》2010,8(6):1569-1601
The M
w = 8.0 Wenchuan earthquake of May 12, 2008, caused destruction over a wide area. The earthquake cost more than 69,000 lives
and the damage is reported to have left more than 5 million people homeless. It is estimated that 5.36 million buildings were
destroyed and 21 million buildings were damaged in Sichuan and the nearby provinces. Economic losses due to the event are
estimated to be 124 billion USD. From a field reconnaissance trip conducted in October 2008, it is evident that the combination
of several factors, including mountainous landscape, strong ground shaking, extensive landslides and rock-falls, has exacerbated
the human and economic consequences of this earthquake. Extensive damage occurred over a wide area due to the shear size of
the earthquake rupture combined with poor quality building construction. In order to investigate the ground shaking during
the earthquake, we have conducted a strong ground motion simulation study, applying a hybrid broadband frequency technique.
The preliminary results show large spatial variation in the ground shaking, with the strongest ground motions along the fault
plane. The simulation results have been calibrated against the recorded ground motion from several near-field stations in
the area, and acceleration values of the order of 1 g are obtained, similar to what was recorded during the event. Comparison
with the damage distribution observed in the field confirms that the effect of fault rupture complexity on the resulting ground
motion distribution also controls to a large extent the damage distribution. The applied simulation technique provides a promising
platform for predictive studies. 相似文献
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Violaine Combier Satish C. Singh Mathilde Cannat Javier Escartin 《Earth and Planetary Science Letters》2008,272(1-2):19-28
We study the relationships between the seafloor structures and the axial magma chamber geometry in the 9°N overlapping spreading center (OSC) area on the fast spreading East Pacific Rise (EPR). Our observations are based on a new high resolution bathymetric map of the 9°N OSC area derived from picks of the seafloor arrival on 3D seismic data, and on previously published data that constrain the presence and distribution of melt below the 9°N OSC. Differences in the orientation of structures between the seafloor and the magma chamber indicate a sharp change in principal stress directions with depth, suggesting that the brittle crust above the melt sill is decoupled from the melt sill itself and the ductile crust underlying it. The stress-field within the brittle upper crust results from a local interaction of the two overlapping spreading centers, whereas the stress-field in the crust below the melt sill corresponds to the regional stress-field imposed by plate separation. Given this mechanical structure of the crust, the melt sill shape and location appear to be controlled by the following factors: the location of the deep melt source below the melt sill, the ambient stress-field at the depth of the melt sill, and the stress-field in the brittle upper crust above the melt sill, which thermally shapes the roof of the melt sill through repeated eruptions. 相似文献
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Jean-Pierre Rivet Farrokh Vakili Olivier Lai David Vernet Mathilde Fouché William Guerin Guillaume Labeyrie Robin Kaiser 《Experimental Astronomy》2018,46(3):531-542
More than sixty years after the first intensity correlation experiments by Hanbury Brown and Twiss, there is renewed interest for intensity interferometry techniques for high angular resolution studies of celestial sources. We report on a successful attempt to measure the bunching peak in the intensity correlation function for bright stellar sources with 1 meter telescopes (I2C project). We propose further improvements of our preliminary experiments of spatial interferometry between two 1 m telescopes, and discuss the possibility to export our method to existing large arrays of telescopes. 相似文献
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Jean-Marie Auzende Mathilde Cannat Pascal Gente Jean-Pierre Henriet Thierry Juteau Jeffrey Karson Yves Lagabrielle Catherine Mével Maurice Tivey 《地学学报》1994,6(2):143-148
The objective of the 20 Nautile dives of the recent Kanaut cruise was to study the southern wall of the Kane Fracture Zone from its eastern intersection with the Mid-Atlantic Ridge (MAR) to 5 Myr in age. The geological mapping shows four successive massifs, wrench faulted and slightly tilted. The transform-facing walls of these massifs exhibit outcrops of fresh and serpentinized peridotites, gabbros and basalts. The entire crustal exposure is cataclased and metamorphosed to greenschist facies. 相似文献
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Fatimah Sulu-Gambari Mathilde Hagens Thilo Behrends Dorina Seitaj Filip J. R. Meysman Jack Middelburg Caroline P. Slomp 《Estuaries and Coasts》2018,41(4):921-939
Recycling of phosphorus (P) from sediments contributes to the development of bottom-water hypoxia in many coastal systems. Here, we present results of a year-long assessment of P dynamics in sediments of a seasonally hypoxic coastal marine basin (Lake Grevelingen, the Netherlands) in 2012. Sequential phosphorus extractions (SEDEX) and X-ray absorption spectroscopy (XAS) indicate that P was adsorbed to Fe-(III)-(oxyhydr)oxides when cable bacteria were active in the surface sediments in spring. With the onset of summer hypoxia, sulphide-induced dissolution of the Fe-(III)-(oxyhydr)oxides led to P release to the pore water and overlying water. The similarity in authigenic Ca-P concentrations in the sediment and suspended matter suggest that Ca-P is not formed in situ. The P burial efficiency was ≤ 32%. Hypoxia-driven sedimentary P recycling had a major impact on the water-column chemistry in the basin in 2012. Water-column monitoring data indicate up to ninefold higher surface water concentrations of phosphate in the basin in the late 1970s and a stronger hypoxia-driven seasonal P release from the sediment. The amplified release of P from the sediment in the past is attributed to the presence of a larger pool of Fe-bound P in the basin prior to the first onset of hypoxia. Given that P is not limiting, primary production in the basin has not been affected by the decadal changes in P availability and recycling over the past 40 years. The changes in P dynamics on decadal time scales were not recorded in sediment profiles of total P or organic C/total P. 相似文献
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ABSTRACTSkempton coefficient B is commonly used to evaluate the saturation of a sample before the shearing stage in a triaxial test. For unsaturated soils, measuring the degree of saturation Sr at the end of the consolidation stage is very difficult whereas measuring Skempton coefficient B is very simple. Using this coefficient to obtain Sr of a sample in a triaxial apparatus without complex procedures might be an improvement, especially as regards testing procedures for unsaturated soils. Different authors have proposed a relationship between these two parameters based on the hypothesis that a variation of B coefficient with Sr is mostly due to the compressibility of air in the pores. However, the presence of air as a fluid phase gives rise to suction after the equilibrium is reached inside the sample leading to an increase in stiffness. Based on this observation, this article presents a new relationship that enables Sr to be evaluated with a given Skempton coefficient taking into account not only the initial void ratio and the isotropic elastic modulus but also the suction and the elastoplastic behaviour of the soil. The results of the proposed approach are then confronted with the original relationship and compared to experimental data. 相似文献