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71.
Natural Hazards - The ranking of events is a powerful tool to evaluate risks of catastrophic events. Here we analyze the rank-statistical profile of the North Atlantic annual accumulated cyclone... 相似文献
72.
Gerardo Rodríguez-Fuentes Sabine Devautour-Vinot Sekou Diaby François Henn 《Physics and Chemistry of Minerals》2011,38(8):613-621
Purified natural clinoptilolite from the Tasajeras deposit, Cuba, and some of its metal exchanged forms are studied, at the
dehydrated state, by means of dielectric relaxation spectroscopy (DRS) using two different modus operandi: complex impedance
spectroscopy and dielectric dynamic thermal analysis. Data analysis yields the determination of the extra-framework cation
(EFC) population into the various possible crystallographic sites of the zeolitic framework as well as of the activation energy
characterizing the localized hopping mechanism of EFC. First, it is shown that the DRS responses obtained here match well
with the previous reported data, which were previously localized EFCs in positions close to M1 and M2 sites when the clinoptilolite
is modified to almost homoionic form. From this outcome, it can be concluded that all EFCs are in the same crystallographic
situation regarding solvation or, in other terms, that no steric effect can be taken into account to explain cationic selectivity.
Second, based on the assumption that the activation energy for EFC hopping is directly connected to the EFC/framework interaction
and on simple thermodynamics consideration, we show this interaction does not govern the EFC exchange reaction. So, it is
emphasized that EFC/H2O interaction is the key factor for cation exchange selectivity. 相似文献
73.
Gerardo Herrera Davide Notti Juan Carlos Garc��a-Davalillo Oscar Mora Geraint Cooksley M��nica S��nchez Alain Arnaud Michele Crosetto 《Landslides》2011,8(2):195-206
This paper describes the use of the Stable Point Network technique, a Persistent Scatterer Interferometry SAR technique, for
the analysis of the Portalet landslide area (Central Pyrenees, Spain). For this purpose, different SAR datasets acquired by
ERS-1, ERS-2, ENVISAT and TerraSAR-X satellites have been analysed. The use of different SAR images acquired by satellite
radar sensors operating at different microwave lengths has allowed for a comparative assessment and illustration of the advantages
and disadvantages of these satellites for landslide detection and monitoring. In the introduction, differential interferometry
and the study area are briefly described. Then the specifics of the SPN processing and the results of the different datasets
are described and compared. In Analysis of the results: the Portalet landslide area, the Portalet landslide area is introduced
and the radar displacement measurements are analysed with available geo-information data. Additionally, X-band measurements
are compared with those gathered by a ground-based SAR for a previous project. Finally, the most relevant conclusions of this
work are discussed. 相似文献
74.
Oliviero M. Moretti P.F. Severino G. Straus Th. Magrì M. Tripicchio A. 《Solar physics》2002,209(1):21-35
The intensity and velocity fluctuations, observed simultaneously, are a powerful diagnostic tool of the dynamics of the solar
atmosphere. The phase relation between the fluctuations can improve our knowledge of the solar background, its relation with
the acoustic sources, and its interaction with the solar acoustic oscillations. Furthermore, the opposite asymmetries observed
along the p-mode line profiles in the intensity and velocity power spectra contain information about the source of the solar acoustic
oscillations. For these reasons, it is relevant to study the height dependence of the asymmetries and phases in the solar
atmosphere. In this paper, we present the results from the analysis of observations performed by the VAMOS instrument in the
potassium 769.9 nm line and Na i D lines, and compare the measured phases with those obtained at different layers in the solar
atmosphere by different instruments, spanning from the base of the photosphere to the low chromosphere. 相似文献
75.
New rurality and the experience of place: the small rural locality of La Niña,Buenos Aires,Argentina
This paper presents a cultural geographic approach for understanding local social processes of territorial re-appropriation taking place in response to non-local forces and interests. This approach is applied to the small rural locality of La Niña, in Buenos Aires Province, Argentina. The small village of La Niña is currently in a locally-led process of recovering from a recent depopulation trend caused mainly by the irruption of transnational agribusiness. As economic opportunities have dwindled in the last decades, more recently local inhabitants and new settlers have set forth diverse strategies aimed at mitigating the effects of depopulation on the social structure. We focus our attention on the way the living experience of place is involved in all these strategies. We contend that despite economic and cultural homogenization caused by globalization, the experience of place is a permanent though ever-changing aspect of social life. Our research was based on archival and hemerographic surveys and ethnographic field techniques, encompassing participatory observation, semistructured and in-depth interviews with social and government leaders and local producers as well as field landscape appraisals. 相似文献
76.
77.
Roberto Sarro Rosa María Mateos Inmaculada García-Moreno Gerardo Herrera Paola Reichenbach Luís Laín Carlos Paredes 《Landslides》2014,11(3):493-503
The Son Poc rockfall took place on the 6th of March 2013 in the municipality of Bunyola, on the southern side of the Tramuntana Range (Mallorca) and after a rainy and cold period on the region. A volume of rock of 4.000 m3 was detached from the cliff crowning the peak falling down by toppling. The impact of the boulder caused its fragmentation, and numerous boulders bounced and rolled downslope with volumes from 1 to 35 m3, following two trajectories: southwest (SW) and southeast (SE). The SE trajectory, with a larger runout (376 m), reached an urban area, where some of the boulders hit the roofs and walls of nearby houses, stopping others in their gardening areas. Fortunately, no fatalities occurred despite of the presence of some people at that moment, but the event caused great concern in a region which lives from and for tourism. The Son Poc rockfall has been simulated using RocPro3D software which uses GIS technology to produce 3D rockfall trajectories lines, estimated velocity and energy of falling blocks, as well as bounce heights, impacts, and stopping points. The results are in agreement with field observations and with a very good accuracy between real and modeled outcomes. 相似文献
78.
DInSAR analysis of ALOS PALSAR images for the assessment of very slow landslides: the Tena Valley case study 总被引:2,自引:2,他引:0
Juan Carlos García-Davalillo Gerardo Herrera Davide Notti Tazio Strozzi Inmaculada Álvarez-Fernández 《Landslides》2014,11(2):225-246
In this work we analyse the performance of advanced land observing satellite (ALOS) phased array type L-band syntetic aperture radar (PALSAR) images for mapping and monitoring of very slow landslides using conventional differential interferometry in the Tena Valley (Central Pyrenees, Spain). These results are compared with those retrieved in previous works where multi-band advanced differential interferometric synthetic aperture radar (DInSAR) analysis was performed for the same area using PSI techniques. The study area is largely underlain by slates (ca. 80 %) where large deep-seated very slow earth flows are dominant. The results reveal that DInSAR analysis is able to measure displacements of landslides with a greater spatial coverage than PSI analysis, but for a lower amount of them (nine against 51). Overall, the combination of the DInSAR and multi-band PSI analysis permitted to map and monitor 68 % of the landslides in Tena Valley. From this amount, 63 landslides are considered as active. The main advantage of DInSAR with respect to PSI analysis is the capability to detect faster movements (up to 145 cm?year?1) derived from the 46 days interferograms. That is the case of Sextas and La Selva landslides where an acceleration of the moving mass was measured after intense rainfall periods producing major damages to linear infrastructures. The combination of measured displacement from ALOS interferograms, with the observed damages on the A-136 road, was useful to assess the potential damage that could cause these slow movements. In general, it is demonstrated that even though PSI analysis provides a better performance in terms of landslide mapping, L-band DInSAR analysis provides an added value for landslide hazard assessment through radar remote sensing. For this reason it is necessary to encourage the launch of new satellite missions similar to ALOS PALSAR that could operate with shorter revisiting time periods. 相似文献
79.
Ingo J. Hahn Pablo M. Vergara Julia Baumeister Gerardo E. Soto Uwe Römer 《Natural Hazards》2014,71(1):987-993
Natural catastrophes could damage island biodiversity and ecosystems, and their effects could become devastating if combined with human disturbances. In this study, we determined the effects of the tsunami occurred in Robinson Crusoe Island (Chile) on 27 February 2010 on an endangered soil–plant system. Using data of endemic Cabbage Trees (Dendroseris litoralis Skottsb.) and soil attributes taken before and after the 2010 event, we developed thematic maps to assess the changes in population size and soil substrate of Cabbage Trees caused by the tsunami. We determined that from 153 pre-tsunami (2009) standing Cabbage Trees, only 66 (43 %) survived in 2011, mostly in elevations above 25 m a.s.l. Before the tsunami, 86 (56 %) of Cabbage Trees were established in humus-rich soil sites whereas after the tsunami, this number declined to 53 (35 %). These results represent the first report of a severe population decline after a tsunami and indicate that tsunamis are an important source of species extinction in small oceanic islands not only by reducing the population size but also by reducing the quality of sites for plant growth. 相似文献
80.
Yongjun Wei Shan Jiang Lingmin Tian Liping Wei Jie Jin Juan Severino Pino Ibanhez Yan Chang Xiaodao Wei Ying Wu 《海洋学报(英文版)》2022,41(1):118-131
Coastal zones are active reactors of continental material including that transported by rivers via a series of microbiota-mediated reactions. Nevertheless, current knowledge of the ecology and functioning of the microbiota in coastal areas affected by large riverine inputs remains insufficient on a global scale. Here, an investigation on sediment microbial composition, including taxonomy and metabolic network, as well as their relationship with major benthic reaction substrates, namely carbon, n... 相似文献