2011年日本东北近海地震震源上方的位移

2011年3月11日,一次大的板间地震(MW9.0)发生在日本东北宫城县附近的板块交界处。根据余震分布推测的震源区为约500km长、200km宽的近海区(Japan Meteo-rological Agency,2011)。     

水平定向钻钻孔环形区域施工后评价

近来,人们对水平定向钻穿越施工后钻孔与管壁之间泥浆填充情况给予了关注。为解答该问题,本项研究进行了一系列现场和室内实验,对钻孔与管壁之间泥浆填充情况进行量化评价。研究中选择了粘土和砂土两种土质,分别敷设直径100mm（4in．）、200mm（8in．）、300mm（12in．）,材质为SDR17的高密度聚乙烯（HDPE）管道61m（200ft．）。随后,按1天、1周、2周、4周、1年的时间间隔开挖管道,观察管道与钻孔孔壁之间土的填充情况,记录填充土体强度,评价泥浆随时间的变化情况,并对土样进行了现场和室内试验。本文介绍了此项研究的主要成果,可为水平定向钻钻孔环形区域完整性评价提供量化信息。研究表明：1）钻孔与管道之间的环形区域填充情况良好,较少有空洞存在。2）在周围土层的固结作用下,充填土土体强度随时间增长。     

Spatial distribution and corresponding determining factors of metal concentrations in surface sediments of Beppu Bay, southwest Japan

This study determined the factors contributing to the spatial distribution of 14 metal concentrations in the surface sediments of Beppu Bay on the basis of comparisons of the organic geochemical properties and environmental parameters through principal component analysis (PCA) and redundancy analysis (RDA). The results of PCA and RDA showed that the concentrations of V, Cr, Co, and As were closely related to the distances between the sampling sites and the Oita River. This indicated that these metals originated from the river's drainage area. The Mn, Cu, Mo, and Cd concentrations were related to the water depth. These results indicated that the Mo, Cd, and Cu deposition processes were controlled by oxygen depletion, and that these elements accumulated in the deeper parts of the bay under anoxic conditions.     

Heavy metal distribution in sediments of Muthupettai mangroves, south east coast of India

Core sediments from the Muthupettai mangroves on the southeast coast of India were analyzed for soil texture,total nitrogen,organic carbon,phosphorus and heavy metals(Fe,Mn,Cr,Cu,Ni,Pb,Zn and Cd).The distinct seasonal variation in the distribution of metals in the sediments was observed.The minimum concentration was recorded in river mouth and the maximum was in lagoon.High metal concentration in sediment was observed during monsoon and low concentration in summer.The total nu-trient in lagoon and river mouth was recorded in the range of 4.528 to 8.526 mg g-1 for organic carbon,2.213 to 10.5 mg g-1 for nitro-gen and 0.824 to 7.22 mg g-1.     

Human stewardship or ruining cultural landscapes of the ancient Tula wells, southern Ethiopia

This article uses the concepts of "human stewardship" and "ruined landscape" as a theoretical framework for analysing the community's perception of landscape change in the ancient tula well system of Borana in southern Ethiopia. The ancient tula well system, the main permanent water source, has been in operation for more than five centuries and it closely links human activity and the environment. The welfare of the tula well system and the performance of the Borana pastoral system are directly related. Borana management of the tula wells uses concepts such as laaf aadaa seeraa and laaf bade to differentiate between ‘land managed by customary laws’ (hereafter human stewardship) and ‘lost’ or ‘ruined’ land (laaf bade). The cultural landscapes of the ancient wells have undergone changes from ecosystems featuring ‘human stewardship’ (before the 1960s), that is, laaf aadaa seeraa to ‘ruined landscapes’ (after the 1960s), that is, laaf bade. Our interest is in understanding how the Borana perceive the impact of land use changes from these two conceptual perspectives. In group discussions, key informant interviews and household surveys across five of the nine well clusters, we found that the society described the changed tula cultural landscape in terms of drivers of well dynamics (i.e. use and disuse), break up of land use zonations, patterns of human settlement (traditional versus peri-urban), expansion of crop cultivation, and changes in environmental quality. Using the two concepts, we analysed linkages between changing patterns of land use that transformed the system from laaf aadaa seeraa, which ensured human stewardship, to laaf bade, which resulted in ruined landscapes. From these we analysed environmental narratives that showed how the society differentiated the past human stewardship that ensured sustainable landscape management from the present ruining of tula well cultural landscapes.     

BL Lacertae： Hard Optical Spectrum and GeV γ-ray Emission

The spectral energy distribution (SED) of the γ-ray flare observed in July 1997 in BL Lacertae is re-considered. It is pointed out that the optical observations made by Webb et al. showed the associated optical flare has a hard spectrum (the average spectral index αopt～0.48, Fν∝ν^-α), and the ASCA observations made by Tanihata et al. showed very steep spectra in the soft X-ray band (0.7-1.5 keV) (αx～3-4). We find that the flux densities and spectral indices in both the optical and soft X-ray bands are closely consistent with a ‘canonical‘ synchrotron spectrum emitted by relativistic electrons of a power-law energy distribution with a high energy cutoff, and thus the peak of the SED of the synchrotron radiation (in representation of νFν) is located in the EUV - soft X-ray bands. Therefore, the GeV γ-ray emission observed in the July 1997 outburst may be mainly due to the synchrotron self-Compton (SSC) process, contrasting with the current explanations in terms of external radiation Compton (ERC) process, in which the seed photons are mostly taken to be the UV emission from the clouds of the broad emission line region. We argue that the hard optical spectra observed during the γ-ray outburst may be an important signature for the acceleration of high energy electrons (γe-10^4) in the γ-ray emitting region.     

喜马拉雅的结构和构造——关于地球物理观测的概略小结

喜马拉雅地区的主要结构和构造与岛弧的相似 ,但被轻的印度陆壳 (不是洋壳 )消亡引起的作用所改造。恒河盆地下的前第三纪基底的表面形态与海洋深海槽的表面形态相似 ,而中印高原是外部地形隆起的追忆记载。印度地盾上的重力异常与朝向海洋的岛弧的重力异常相似 ,并具有岩石圈在深海沟处向下弯曲和在外缘隆起处向上挠曲的模式。断裂面的分解式说明印度岩石圈确实弯曲 ,然后以低角度向喜马拉雅山俯冲。来自印度和岛弧的有关这方面的资料说明了同一个现象。大西洋和印度洋的海洋地球物理资料 ,可以对最后 70 Ma的印度和欧亚地质史加以恢复。一种急剧减缩作用 ,速率大致为 1 0 0 mm/ a。大概在 40 Ma前接近或稍晚于地质上所推定的碰撞时间。印度向巨大深处的消亡作用假定为漂浮的大陆壳所阻碍。印度地壳的浮力可能导致收敛速率的降低 ,但不是停止。虽然与新断裂的产生以及印度板片一个个地向上推置 ,形成山脉带有关 ,但地震记录表明 :沿低角底断裂面 (可在主边界断裂上或紧邻主边界断层 )的俯冲断裂作用 ,使敛合作用继续发生。重力异常与这种解释是一致的。假若喜马拉雅是由印度次大陆古老板片北缘的断裂作用和仰冲板片所建立起来的 ,那么与重力资料说明有 30 0— 40 0 km的缩短是一致的。在喜马拉雅山收缩     

Stratigraphy of Upper Cretaceous──Paleogene deposits of northwestern Zeya──Burya sedimentary basin

In the northwestern Zeya──Bureya sedimentary basin, the authors studied coal deposits, including Ivanovsko-Erkovetskyu brown coal square on which is worked off largest Erkovetsky field of brown coal, extending to south flank of the Mesozoic──Cenozoic Belogor'e depression. The verified stratigraphic scheme of the coalfield sedimentary sequence is substantiated by palynological data on core samples from 18 boreholes sampled in the course of detailed prospecting and by paleobotanical analysis of sections in the Yuzhnyi sector of the coalfield. Sections of the Erkovtsy, Arkhara Boguchan, and Raichikha brown-coal mines are correlated. Stratigraphic subdivisions distinguished in the studied sedimentary succession are the middle and upper Tsagayan subformations (the latter incorporating the Kivda Beds), Raichikha and Mukhino formations.     

Late Cenozoic Tectonic Deformation in the Dongsha Islands and Adjacent Sea Area

Dongsha Island and the adjacent sea area locate at the northern continental margin of the South China Sea (SCS), and is connected to the east by the Manila Trench. Analyses of seismic stratigraphy and gravity, magnetic and drilling wells data led to the discovery of three post-fault sequences (Ⅴ, Ⅵ, Ⅶ). Extensive tectonic uplift, magma activity and erosion occurred in Dongsha Island and the adjacent area, where most of the faults in the northeastern SCS were still active during Pliocene and Quaternary. Two groups of faults trending NEE and NW were developed during Late Cenozoic. We conclude that three important tectonic movements, especially Dongsha movement(4.4 - 5.2 Ma) and Liuhua movement (1.4 - 1.89 Ma), controlled the structural framework in the Dongsha rise; whose deformation in the east is stronger than that in the west and whose stress field variation suggests that the tectonic uplift in the study area contributed to magmato-tectonic events correlated to the main collision phases between the East China and Taiwan 5 - 3 and 3 - 0 Ma ago.