对J C Savage关于“沿圣安德烈斯断层蠕变部分的无震滑动和垂直断层应变”所作评论的回复     

F Rolandone  R Burgmann  D C Agnew  I A Johanson  D C Templeton  M A d'Alessio  S J Titus  C DeMets  B Tikoff  周平博 《国际地震动态》2010,(6):39-40

太平洋板块与希拉内华达大峡谷微板块间的相对运动大多数是通过沿圣安德烈斯断层的走向滑动来调整的。在圣安德烈斯断层中部（CSAF）,沿走向的滑动近于以无震断层蠕变的形式发生（Thatcher,1979;Titus等,2006;Rolandone等,2008;Ryder and Burgmann,2008）。  相似文献   

Fate and tidal transport of butyltin and mercury compounds in the waters of the tropical Bach Dang Estuary (Haiphong, Vietnam)     

Navarro P  Amouroux D  Thanh ND  Rochelle-Newall E  Ouillon S  Arfi R  Van TC  Mari X  Torréton JP 《Marine pollution bulletin》2012,64(9):1789-1798

In this work, two field campaigns were performed in July 2008 (wet season) and March 2009 (dry season) to produce original data on the concentration, partition and distribution of mercury and butyltin compounds along the tropical Bach Dang Estuary located in North Vietnam (Haiphong, Red River Delta). The results demonstrate that mercury and butyltin speciation in the surface waters of this type of tropical estuary is greatly affected by the drastic changes in the seasonal conditions. During high river discharge in the wet season, there was a large estuarine input of total Hg and tributyltin, while the longer residence time of the waters during the dry season promotes increasing MMHg formation and TBT degradation. Although most of the Hg and TBT is transported into the estuary from upstream sources, tidal cycle measurements demonstrate that this estuary is a significant source of TBT and MMHg during the wet (～3kgTBT/day) and dry (～3gMMHg/day) seasons.  相似文献   

Heavy metals contamination levels at the Coast of Aliağa (Turkey) ship recycling zone   总被引：1，自引：0，他引：1  

Neşer G  Kontas A  Unsalan D  Uluturhan E  Altay O  Darılmaz E  Küçüksezgin F  Tekoğul N  Yercan F 《Marine pollution bulletin》2012,64(4):882-887

Alia?a Bay is one of the most important maritime zones of Turkey where shipping activity, shipbreaking industry, steel works and petrochemical complexes exist together. Concentrations of heavy metals and organic carbon in sediment of the Alia?a Bay were investigated to evaluate an environmental risk assessment from metals contamination in 2009-2010. Comparison of the metal concentrations with average shale and Mediterranean background levels revealed that most of the samples from the Alia?a were polluted with Hg, Cd, Pb, Cr, Cu, Zn, Mn and Ni. It was found that Hg, Pb, Cu, Zn and Ni levels in Alia?a Bay exceeded the PEL values. Sediments, contaminated with Pb, Cr, Cu, Zn and Ni were considered as heavily polluted per the SQG.  相似文献   

The use of dinoflagellate cysts to separate human-induced from natural variability in the trophic state of the Po River discharge plume over the last two centuries   总被引：1，自引：0，他引：1  

Zonneveld KA  Chen L  Elshanawany R  Fischer HW  Hoins M  Ibrahim MI  Pittauerova D  Versteegh GJ 《Marine pollution bulletin》2012,64(1):114-132

To obtain insight into the natural and/or human-induced changes in the trophic state of the distal portion of the Po River discharge plume over the last two centuries, high temporal resolution dinoflagellate cyst records were established at three sites. Cyst production rates appear to reflect the natural variability in the river's discharge, whereas cyst associations reflect the trophic state of the upper waters, which in turn can be related to agricultural development. The increased abundances of Lingulodinium machaerophorum and Stelladinium stellatum found as early as 1890 and 1920 correspond to the beginning of the industrial revolution in Italy and the first chemical production and dispersion of ammonia throughout Europe. After 1955, the increased abundances of these species and of Polykrikos schwartzii, Brigantedinium spp. and Pentapharsodinium dalei correspond to agriculturally induced alterations of the hypertrophic conditions. A slight improvement in water quality can be observed from 1987 onward.  相似文献   

对24种大气成分的热红外天底观测     

L. Clarisse  Y. R＇Honi  P.-F. Coheur  D. Hurtmans  孙玉涛译  杜建国校  崔月菊校 《世界地震译丛》2012,(2):84-88

热红外天底探测仪是观测诸如水汽、二氧化碳和臭氧等大气组分总柱含量或垂直剖面的理想仪器。低于5cm-1光谱分辨率的高分辨率探测仪能够分辨痕量气体细微的光谱特征。在第一台高光谱探测仪IRIS出现的40年后,现在几款改进了仪器特性的仪器已经在轨运行。本文评述了应用热红外天底探测仪观测痕量气体,重点在于红外大气探测干涉仪(IASI)的新近观测。文章介绍了14种非常活泼的痕量气体的典型观测。从天底视角观测气体讲,一些组分属首次报道,包括亚硝酸、呋喃、乙炔、丙基烯、乙酸、甲醛和氰化氢;这些组分是在2009年2月澳大利亚丛林大火的火积云中观测到的。由于能够观测这些大量活性的痕量气体,所以我们关于源排放及其对环境和气候方面影响的知识可能会加深。  相似文献   

西南印度洋超慢速扩张洋脊的岩浆一构造旋回：来自轴部火山洋脊地形变化和深海丘陵样式的证据     

V．Mendel  D．Sauter  C．Rommevaux-Jestin  P．Patriat  F．Lefebvre  L．M．Parson  赵明辉译  张骥潇译 《世界地震译丛》2012,(3):59-80

综合利用洋脊轴部的深拖侧扫声纳资料和轴外的水深数据,研究了超慢速扩张的西南印度洋洋脊处洋壳增生过程的瞬时变化。在洋脊各段的侧扫声纳图像中可以观察到轴部火山洋脊的长度与高度的差异,及这些火山建造不同的变形程度。这些差异是由于轴部火山洋脊处于其生命演化周期的不同发育阶段,包括火山建造期和构造裂解期。利用轴外侧的水深数据确定了每个洋脊段中许多大小均匀的深海丘陵。这些深海丘陵均显示不对称的形状,面向轴部为陡峭的断层崖,背向轴部为平缓倾斜的火山岩斜坡。这些深海丘陵是被运移到两翼的、已被裂解的早期轴部火山洋脊的残留,它们形成于连续的岩浆建造期和构造裂解期之中,即一个岩浆-构造旋回。在厚地壳的洋脊区段观察到大型深海丘陵,而在薄地壳的洋脊区段观察到小型深海丘陵。这说明岩浆供给量控制着深海丘陵的大小。在薄地壳的洋脊区段,深海丘陵有规律地等间隔排列,表明岩浆一构造循环的伪周期性过程持续约0．4ma,比厚地壳的洋脊区段的周期时间短4～6倍。我们认为,有规律的深海丘陵样式与长寿命洋脊段下部几乎恒定的岩浆持续供给有关。相比之下,在岩浆供给急剧减少并极不连续的情况下,不再存在有规律的深海丘陵样式。  相似文献   

Snow cover variation and streamflow simulation in a snow-fed river basin of the Northwest Himalaya   总被引：3，自引：2，他引：1  

Vaibhav SHARMA  V.D.MISHRA  P.K.JOSHI 《山地科学学报》2012,9(6):853-868

Snowmelt is an important component of any snow-fed river system.The Jhelum River is one such transnational mountain river flowing through India and Pakistan.The basin is minimally glacierized and its discharge is largely governed by seasonal snow cover and snowmelt.Therefore,accurate estimation of seasonal snow cover dynamics and snowmeltinduced runoff is important for sustainable water resource management in the region.The present study looks into spatio-temporal variations of snow cover for past decade and stream flow simulation in the Jhelum River basin.Snow cover extent(SCE) was estimated using MODIS(Moderate Resolution Imaging Spectrometer) sensor imageries.Normalized Difference Snow Index(NDSI) algorithm was used to generate multi-temporal time series snow cover maps.The results indicate large variation in snow cover distribution pattern and decreasing trend in different sub-basins of the Jhelum River.The relationship between SCE-temperature,SCE-discharge and discharge-precipitation was analyzed for different seasons and shows strong correlation.For streamflow simulation of the entire Jhelum basin Snow melt Runoff Model(SRM) used.A good correlation was observed between simulated stream flow and in-situ discharge.The monthly discharge contribution from different sub-basins to the total discharge of the Jhelum River was estimated using a modified version of runoff model based on temperature-index approach developed for small watersheds.Stream power - an indicator of the erosive capability of streams was also calculated for different sub-basins.  相似文献   

Sponges as sentinels: patterns of spatial and intra-individual variation in trace metal concentration   总被引：1，自引：0，他引：1  

de Mestre C  Maher W  Roberts D  Broad A  Krikowa F  Davis AR 《Marine pollution bulletin》2012,64(1):80-89

If sponges are to be effective biomonitors we require a better understanding of the spatial scales over which metals vary in these organisms. We determined how concentration of Cd, Zn, Cu, Pb, Hg and Se varied over four spatial scales for two common estuarine sponge species in the Sydney region. We examined variability with a fully nested sampling design; between coastal lakes, within coastal lakes, between sponges and within sponges. Calculation of variance components confirmed that 'within-sponge' variation in Cd, Zn, Cu, Pb and Se concentrations were low (1-14%) relative to the two largest spatial scales (49-98%) examined. In contrast, Hg concentrations exhibited marked variability 'between-sponges' and were below detection at one location. There was little evidence that sponge size was a good predictor of metal concentration. Taken together, these outcomes confirm that fragments of these sponges could be successfully transplanted and therefore show promise as biomonitors of metal contamination.  相似文献   

Long term monitoring of photosystem II herbicides--correlation with remotely sensed freshwater extent to monitor changes in the quality of water entering the Great Barrier Reef, Australia     

Kennedy K  Schroeder T  Shaw M  Haynes D  Lewis S  Bentley C  Paxman C  Carter S  Brando VE  Bartkow M  Hearn L  Mueller JF 《Marine pollution bulletin》2012,65(4-9):292-305

Photosystem II (PSII) herbicides are used in large quantities on agricultural lands adjoining the Great Barrier Reef (GBR). Routine monitoring at 14 sites in inshore waters of the GBR using passive sampling techniques detected diuron (32-94% of sampling periods) at maximum concentrations of 1.7-430ng L(-1) in the relatively pristine Cape York Region to the Mackay Whitsunday Region, respectively. A PSII herbicide equivalent (PSII-HEq) index developed as an indicator for reporting was dominated by diuron (average contribution 89%) and typically increased during the wet season. The maximum PSII-HEq indicates the potential for photosynthetic inhibition of diatoms, seagrass and coral-symbionts. PSII herbicides were significantly positively correlated with remotely sensed coloured dissolved organic matter, a proxy for freshwater extent. Combining these methods provides for the first time the potential to cost-effectively monitor improvements in water quality entering the GBR with respect to exposure to PSII herbicides.  相似文献   

地震预报的回归     

D.Cyranoski  武巴特尔  许洪华  戴翠华 《国际地震动态》2005,(2):1-4

美国地震学家长期回避“预报”这个词。但是由于数据质量的改善和公众对“预报”含义理解的改变,地震学家们回避“预报”的决心也开始动摇。Cyranoski跟踪了关于“预报”的辩论。  相似文献