Seismogenic sources in the Bay of Bengal vis-à-vis potential for tsunami generation and its impact in the northern Bay of Bengal coast

Geodynamic status, seismo-tectonic environment, and geophysical signatures of the Bay of Bengal do not support the occurrence of seismogenic tsunami. Since thrust fault and its intensity and magnitude of rupture are the key tectonic elements of tsunamigenic seismic sources, the study reveals that such characteristics of fault-rupture and seismic sources do not occur in most of the Bay of Bengal except a small segment in the Andaman–Nicobar subduction zone. The inferred segment of the Andaman–Nicobar subduction zone is considered for generating a model of the deformation field arising from fluid-driven source. The model suggests local tsunami with insignificant inundation potential along the coast of northern Bay of Bengal. The bathymetric profile and the sea floor configuration of the northern Bay of Bengal play an important role in flattening the waveform through defocusing process. The direction of motion of the Indian plate makes an angle of about 30° with the direction of the opening of Andaman Sea. The opening of Andaman Sea and the direction of plate motion of the Indian plate results in the formation of Andaman trench where the subducting plate dives more obliquely than that in the Sunda trench in the south. The oblique subduction reduces significantly the possibilities of dominant thrust faulting in the Andaman subduction zone. Further, north of Andaman subduction in the Bengal–Arakan coast, there is no active subduction. On the otherhand, much greater volume of sediments (in excess of 20 km) in the Bengal–Arakan segment reduces the possibilities of mega rupture of the ocean floor. The water depth (≈1,000 m) along most of the northern Bay of Bengal plate margin is not optimum for any significant tsunami generation. Hence, very weak possibility of any significant tsunami is suggested that based on the interpretation of geodynamic status, seismo-tectonic environment, and geophysical signatures of the Andaman subduction zone and the Bengal–Arakan coast.     

Sources and transports of polycyclic aromatic hydrocarbons in the Nanshan Underground River,China

Karst areas have much higher ecological vulnerability and are easy to be contaminated by polycyclic aromatic hydrocarbons (PAHs), which are introduced as health risk pollutants. PAHs ratios were used to understand the sources and transport behavior of PAHs conducted in the karst Nanshan Underground River, China. Water, sediments from the underground river and water, sediments, soil from the surface were collected monthly in 2011 and 2012. Abundant PAHs were found both in the underground river and in the surface system. The detected ΣPAHs concentrations varied from 353 to 13,203 ng L^?1 in the groundwaters and content from 169 to 12,038 ng g^?1 in the sediments of the underground river. The ratios of anthracene to anthracene, plus phenanthrene and fluoranthene to fluoranthene, plus pyrene indicated that PAHs were delivered in the groundwaters from combusted grass, wood, and coal, while in the sediments were a mixture of non-combusted petroleum, grass, wood, coal and combusted grass, wood, coal. The similarities in sources between an underground river and surface system indicated that farmlands play a major role for the transport of PAHs and contamination in the underground river. Karst features are liable for the transport behavior.     

Smoothing supernova data to reconstruct the expansion history of the Universe and its age

We propose a non-parametric method of smoothing supernova data over redshift using a Gaussian kernel in order to reconstruct important cosmological quantities including   H ( z )  and   w ( z )  in a model-independent manner. This method is shown to be successful in discriminating between different models of dark energy when the quality of data is commensurate with that expected from the future Supernova Acceleration Probe ( SNAP ). We find that the Hubble parameter is especially well determined and useful for this purpose. The look-back time of the Universe may also be determined to a very high degree of accuracy (≲0.2 per cent) using this method. By refining the method, it is also possible to obtain reasonable bounds on the equation of state of dark energy. We explore a new diagnostic of dark energy – the ' w -probe'– which can be calculated from the first derivative of the data. We find that this diagnostic is reconstructed extremely accurately for different reconstruction methods even if Ω_{0 m} is marginalized over. The w -probe can be used to successfully distinguish between Λ cold dark matter and other models of dark energy to a high degree of accuracy.     

Reservoir Potential Assessment of the Tortonian–Calabrian Sediments from Offshore Makran(Southwest Pakistan) through a Multidisciplinary Approach

The Tortonian–Calabrian strata of Offshore Makran(Pakistan) is investigated for the purpose of reservoir assessment. The stratigraphy and petrophysics indicate that the Neogene sediments have tight reservoir potential with porosities in the range of 3%–9% and 40%–50% water saturation. The mineralogical cross plots indicate a mixed lithology with an abundance of dolomite and calcite, together with minor quartz content and shale. The seismic interpretation demonstrates medium–high amplitude reflec...     

Electrochemical disinfection for ballast water management: technology development and risk assessment

Ballast water is essential in maintaining the balance and structural integrity of ships during voyage. However, it has created biological invasion threats to the ocean environment. An innovative electrochemical technology was developed in this study. The microorganisms regulated by the International Maritime Organization (D2) were used as the target organisms. It was found that the required energy to meet the D2 was below 0.006 kWh/m3. The size of disinfector (m3) was about 0.5% of treatment flow rate (m3/h). The complete disappearance of chlorine in seawater was achieved after three days. The ballast tank corrosion was not worsened due to the application of technology. The ecotoxicity studies showed no toxic effect on fish, invertebrate, and algae. Finally, the environmental risk assessment showed the treated water did not pose threats to the environment. It can therefore be concluded that the technology provides a cost-effective and environmental friendly solution to ballast water management.     

Paleochannel and paleohydrology of a Middle Siwalik (Pliocene) fluvial system,northern India

Late Cenozoic fresh water molasses sediments (+6000 m thick) deposited all along the length of the Himalayan fore deep, form the Siwalik Supergroup. This paper reports the results of the paleodrainage and paleohydrology of the Middle Siwalik sub-group of rocks, deposited in non-marine basins adjacent to a rising mountain chain during Pliocene. Well-exposed sections of these rocks have provided adequate paleodrainage data for the reconstruction of paleochannel morphology and paleohydrological attributes of the Pliocene fluvial system.     

重庆老龙洞地下河流域水体有机氯农药污染及来源初步研究

为查明重庆老龙洞地下河流域有机氯农药的污染情况及其特征和来源,通过气相色谱-微池电子捕获检测器(GC-μ ECD)检测水体OCPs含量.结果表明研究区水样中受到了有机氯农药不同程度的污染.α-HCH是研究区水体HCHs主要成分,HCHs的残留主要来自于大气长距离传输.DDTs的主要成分各采样点不尽相同.DDTs的输入为历史上工业DDTs的使用且在水体中其主要以好氧转化为主.与国内外河流相比较,老龙洞地下河流域水体有机氯农药含量处于较高水平.     

Polychlorinated biphenyls in the Nanshan Underground River, China

Abstract Karst areas have much higher ecological vulnerability and are easy to be contaminated by polychlorinated biphenyls(PCBs) which are introduced as health risk pollutants.PCBs concentrations were used to understand the transport behavior of PCBs conducted in the karst Nanshan Underground River,China.Water and sediments from the underground river water,and sediments and soil from the surface of the corresponding watershed were collected monthly in 2011 and 2012 and PCBs were analyzed.Seasonal variations were found in concentrations of PCBs both in the waters and sediments.PCBs concentrations varied from 0.3 to 29.9 ng·L-1 in the groundwater,while from 0.1 to 366.1 ng·g-1 in the underground sediments.Correlations were found in concentrations of PCBs in waters and sediments between the underground river and surface systems which indicate that the surface systems play a major role for the transport of PCBs and contamination in the underground river systems.Karst features are liable for the transport behavior.The underground river waters transport PCBs at mean 3 g·day-1.