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31.
R. Sigbjörnsson J. Th. Snæbjörnsson S. M. Higgins B. Halldórsson S. Ólafsson 《Bulletin of Earthquake Engineering》2009,7(1):113-126
This preliminary study aims to investigate a M
w
6.3 earthquake that occurred in South Iceland on Thursday 29 May 2008 at 15:45 UTC. The epicentre was in the Olfus District
between the towns of Selfoss and Hveragerdi. This study examines the data recorded and the damage observed immediately after
the event. Horizontal accelerations of up to 80%g were recorded in the epicentral region and there is visual evidence that
the vertical acceleration exceeded 1 g. The PGA data is compared to a ground motion estimation model developed for the South
Iceland earthquakes in June 2000. In general the basic properties of this event are found to be similar to the characteristics
of the South Iceland earthquakes in June 2000. The duration of strong-motion is short and the intensity attenuates rapidly
with increasing distance. The earthquake action resisted by buildings in the near fault area is inspected through evaluation
of elastic as well as inelastic response spectra. The vast majority of structures seemed to withstand the strong-motion fairly
competently and without significant visual damage due firstly to the low-rise, predominantly reinforced concrete or timber,
style of buildings. Secondly, the short duration of strong-motion contributed to the endurance of structures. 相似文献
32.
A multi‐proxy study of Holocene environmental change recorded in alluvial deposits along the southern coast of the Pampa region,Argentina 下载免费PDF全文
33.
34.
This article explores the causes for differences in the average CO2 emissions intensity of the new passenger car (NPC) fleet in member states (MS) across Europe. Although EU policies mitigating CO2 emissions from NPCs have been in place since 1999, MS strongly diverge in the absolute amount and relative change in emissions over the last decade. The authors employ a qualitative approach to analyse the factors, in particular national vehicle taxes, contributing to this divergence and the relative contribution of national and European policies in reducing national CO2 emissions from NPCs. The analysis shows that there has been a significant reduction in CO2 emissions intensity of NPCs since 2007 across most MS, compared with the six years previous to that date. This would indicate that EU-wide policies, such as the CO2 vehicles regulation, along with the economic recession in 2008, have influenced national NPC CO2 emissions. Generally, countries with CO2-differentiated vehicle taxes are observed as more likely to have achieved greater reductions in CO2 emissions. However, over the same period there have been many confounding factors, such as economic instability in the EU, that also influence NPC emissions. Using more detailed case study analyses of six countries, the authors find that there is scope for well-designed national vehicle tax policies to drive NPC emissions down further than the EU average. In countries with the highest success rate, such as the Netherlands, the design of the vehicle tax, as part of a well-aligned policy package, has been very important in delivering the biggest reductions in CO2 emissions from NPCs.
POLICY RELEVANCE
The transport sector continues to be an intractable source of CO2 emissions. Governments around the world are seeking effective policies to deal with the increase in passenger car CO2 emissions appropriate to their own circumstances. This article examines the experience of EU MS with CO2-differentiated vehicle taxes in reducing CO2 emissions in the context of other national and international contributing factors. It should therefore both be useful to policy makers and contribute to climate policy research in general. 相似文献
35.
DEFORMATIONAL BEHAVIOURS OF ALLUVIAL UNITS DETECTED BY ADVANCED RADAR INTERFEROMETRY IN THE VEGA MEDIA OF THE SEGURA RIVER,SOUTHEAST SPAIN 下载免费PDF全文
36.
Óscar A. Barocio-León Roberto Millán-Núñez Eduardo Santamaría-del-Ángel Adriana González-Silvera Charles C. Trees 《Journal of Oceanography》2006,62(6):873-885
We have estimated the spatial variability of phytoplankton specific absorption coefficients (a*
ph
) in the water column of the California Current System during November 2002, taking into account the variability in pigment
composition and phytoplankton community structure and size. Oligotrophic conditions (surface Chl < 0.2 mg m−3) dominated offshore, while mesotrophic conditions (surface Chl 0.2 to 2.0 mg m−3) where found inshore. The specific absorption coefficient at 440 [a*
ph
(440)] ranged from 0.025–0.281 m2mg−1 while at 675 nm [a*
ph
(675)] it varied between 0.014 and 0.087 m2mg−1. The implementation of a size index based on HPLC data showed the community structure was dominated by picoplankton. This
would reduce the package effect in the variability of a*
ph
(675). Normalized a
ph
curves were classified in two groups according to their shape, separating all spectra with peaks between 440 and 550 nm as
the second group. Most samples in the first group were from surface layers, while the second group were from the deep chlorophyll
maximum or deeper. Accessory photoprotective pigments (APP) tended to decrease with depth and accessory photosynthetic pigments
(APS) to increase, indicating the importance of photoprotective mechanisms in surface layers and adaptation to low light at
depth. Samples with higher ratios of APP:APS (>0.4) were considered as phytoplankton adapted to high irradiances, and lower
ratios (<0.26) as adapted to low irradiances. We found a good relationship between APP:APS and a*
ph
(440) for the deeper layer (DCM and below), but no clear evidence of the factors causing the variability of a*
ph
(440) in the upper layer. 相似文献
37.
Óscar Pueyo Anchuela Antonio M. Casas‐Sainz Emilio L. Pueyo Andrés Pocoví Juan Andrés Gil Imaz 《地学学报》2013,25(4):307-314
Magnetic susceptibility in rocks is the sum of the contributions of different magnetic particles (paramagnetic, diamagnetic and ferromagnetic s.l.). These contributions can be measured at variable temperatures or at variable fields (hysteresis loops). Both are time‐consuming techniques that cannot be routinely used in magnetic fabrics analysis. In this study, we propose a simplified method to determine the ferro‐ and paramagnetic contributions to the susceptibility, based on the discrete measurement of susceptibility at two different fields (near 0 and 2.5 T). The results obtained in samples from the Southern Pyrenees and Ebro Basin indicate that the ferromagnetic contribution vary considerably within homogeneous susceptibility values and within the expected range of paramagnetic values. Standard bulk susceptibilities higher than 200 10?6 SI contribute significantly to the ferromagnetic fraction (>50% on average). 相似文献
38.
39.
The Tyne Gap is a wide pass, situated between the Scottish Southern Uplands and the English Pennines that connects western and eastern England. It was a major ice flow drainage pathway of the last British–Irish Ice Sheet. This study presents new glacial geomorphological and sedimentological data from the Tyne Gap region that has allowed detailed reconstructions of palaeo‐ice flow dynamics during the Late Devensian (Marine Isotope Stage 2). Mapped lineations reveal a complex palimpsest pattern which shows that ice flow was subject to multiple switches in direction. These are summarised into three major ice flow phases. Stage I was characterised by convergent Lake District and Scottish ice that flowed east through the Tyne Gap, as a topographically controlled ice stream. This ice stream was identified from glacial geomorphological evidence in the form of convergent bedforms, streamlined subglacial bedforms and evidence for deformable bed conditions; stage II involved northerly migration of the Solway Firth ice divide back into the Southern Uplands, causing the easterly flow of ice to be weakened, and resulting in southeasterly flow of ice down the North Tyne Valley; and stage III was characterised by strong drawdown of ice into the Irish Sea Ice Basin, thus starving the Tyne Gap of ice and causing progressive ice sheet retreat westwards back across the watershed, prior to ice stagnation. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
40.
Chris D. Clark Richard C. Chiverrell Derek Fabel Richard C. A. Hindmarsh Colm Ó Cofaigh James D. Scourse 《第四纪科学杂志》2021,36(5):673-680
Motivated to help improve the robustness of predictions of sea level rise, the BRITICE-CHRONO project advanced knowledge of the former British–Irish Ice Sheet, from 31 to 15 ka, so that it can be used as a data-rich environment to improve ice sheet modelling. The project comprised over 40 palaeoglaciologists, covering expertise in terrestrial and marine geology and geomorphology, geochronometric dating and the modelling of ice sheets and oceans. A systematic and directed campaign, organised across eight transects from the continental shelf edge to a short distance (10s of kilometres) onshore, was used to collect 914 samples which yielded 639 new ages, tripling the number of dated sites constraining the timing and rates of change of the collapsing ice sheet. This special issue synthesises these findings of ice advancing to the maximum extent and its subsequent retreat for each of the eight transects to produce definitive palaeogeographic reconstructions of ice margin positions across the marine to terrestrial transition. These results are used to understand the controls that drove or modulated ice sheet retreat. A further paper reports on how ice sheet modelling experiments and empirical data can be used in combination, and another probes the glaciological meaning of ice-rafted debris. 相似文献