A Study of Largest Active Region AR12192 of 24th Solar Cycle Using Fractal Dimensions and Mathematical Morphology

Solar System Research - An active region (AR) of the sun is an area of strong magnetic field. Sunspots are frequently formed in an AR. Solar activity exhibits in the form of solar flares and...     

Rockburst Risk Analysis During High-Hard Roof Breaking in Deep Mines

Natural Resources Research - Mining operations continue to advance to greater depths to address the demand and supply of coal. However, deep mining occurs in complex and dangerous environments...     

Landslide inventory and susceptibility assessment using multiple statistical approaches along the Karakoram highway,northern Pakistan

China-Pakistan Economic Corridor(CPEC)is a framework of regional connectivity,which will not only benefit China and Pakistan but will have positive impact on Iran,Afghanistan,India,Central Asian Republic,and the region.The surrounding area in CPEC is prone to frequent disruption by geological hazards mainly landslides in northern Pakistan.Comprehensive landslide inventory and susceptibility assessment are rarely available to utilize for landslide mitigation strategies.This study aims to utilize the high-resolution satellite images to develop a comprehensive landslide inventory and subsequently develop landslide susceptibility maps using multiple techniques.The very high-resolution(VHR)satellite images are utilized to develop a landslide inventory using the visual image classification techniques,historic records and field observations.A total of 1632 landslides are mapped in the area.Four statistical models i.e.,frequency ratio,artificial neural network,weights of evidence and logistic regression were used for landslide susceptibility modeling by comparing the landslide inventory with the topographic parameters,geological features,drainage and road network.The developed landslides susceptibility maps were verified using the area under curve(AUC)method.The prediction power of the model was assessed by the prediction rate curve.The success rate curves show 93%,92.8%,92.7%and 87.4%accuracy of susceptibility maps for frequency ratio,artificial neural network,weights of evidence and logistic regression,respectively.The developed landslide inventory and susceptibility maps can be used for land use planning and landslide mitigation strategies.     

Diversity and Abundance of Scleractinian Corals in the East Coast of Peninsular Malaysia: A Case Study of Redang and Tioman Islands

Ocean Science Journal - The species lists of scleractinian hard corals in Peninsular Malaysia have not been updated for 15 years. The present study aimed to determine the diversity and abundance...     

Applications of variogram modeling to electrical resistivity data for the occurrence and distribution of saline groundwater in Domail Plain,northwestern Himalayan fold and thrust belt,Pakistan

This paper studies electrical resistivity dataset acquired for a groundwater study in the Domail Plain in the northwestern Himalayan section of Pakistan. Through a combination of geostatistical analysis, geophysical inversion and visualization techniques, it is possible to re-model and visualize the single dimension resistivity data into 2D and 3D space. The variogram models are utilized to extend the interpretation of the data and to distinguish individual lithologic units and the occurrence of saline water within the subsurface. The resistivity data has been calibrated with the lithological logs taken from the available boreholes. As such the alluvial system of the Domail Plain has formed during episodes of local tectonic activity with fluvial erosion and deposition yielding coarse sediments with high electrical resistivities near to the mountain ranges and finer sediments with medium to low electrical resistivities which tend to settle in the basin center. Thus a change is depositional setting happened from basin lacustrine environment to flash flooding during the Himalayan orogeny. The occurrence of rock salt in the northern mountains has imparted a great influence on the groundwater quality of the study area. The salt is dissolved by water which infiltrates into the subsurface through the water channels. Variogram aided gridding of resistivity data helps to identify the occurrence and distribution of saline water in the subsurface.     

Diffusion of China’s coal-fired power generation technologies: historical evolution and development trends

Natural Hazards - With increasing environmental pressure and the promotion of structural reforms on the supply side, a trend of transformation and upgrading is inevitable in coal-fired power...     

Analysis of wheat farmers’ risk perceptions and attitudes: evidence from Punjab,Pakistan

Natural Hazards - Agriculture involves multiple risks of which environmental and production threats are major ones. Farmers’ risk attitudes and risk perceptions have a significant role in...     

Use of receiver functions in wide-angle controlled-source crustal data sets

First-arrival waveforms remain underutilized in crustal refraction–reflection seismology by mostly reducing them to traveltime picks. However, as in earthquake seismology, the waveforms also contain important information about shallow near-receiver structures. We illustrate the use of three-component waveform analysis on the records from the ACCRETE wide-angle data set (SE Alaska and British Columbia; 1994), apply the Receiver Function (RF) methodology to the codas of P -wave arrivals, and draw two important conclusions. First, the P -wave polarization azimuths are found to be controlled by the near-receiver structures and virtually unrelated to the source–receiver backazimuths, from which they deviate by up to ∼40°. This observation might be important for studies of anisotropy and also for earthquake RF studies. Second, after correcting for the polarization azimuths, clear P / S mode conversions are reliably detected within 80–400 ms following the primary arrivals. The conversions are interpreted as originating at the base of the sedimentary cover of the fjord channel. In most cases, imaging of the basement requires only several records; however, notable exceptions are also found and interpreted as caused by multipathing, localized scattering, and onsets of crustal and Moho reflections. The ACCRETE example shows that RF methodology could be useful for constraining sediment thickness and deriving P - and S -wave receiver statics in land refraction surveys where collocated reflection profiles are not available. In addition, RFs from repeatable controlled sources could be useful for testing and calibration of RF techniques.     

Spatial distribution of trace elements associated with organic carbon along the Beiyun River basin,Beijing,China

Pollution resulting from terrestrial and aquatic trace elements has become a severe problem across the world. Organic carbon(OC) content has a high affinity for metallic contaminants and it acts as a significant sink for trace elements. The decomposition of OC content directly influences the bioavailability of trace elements. The decomposition of OC content and OC distribution vary spatially, these processes affect the release of trace elements and need further research. In the current study, se...     

塔里木盆地西部白垩纪—古近纪海相地层框架及对重大地质事件的记录

塔里木盆地西部白垩纪—古近纪发生了大规模的海侵事件,形成一个喇叭状向西开口的海湾,该海湾属于东特提斯洋的一个分支。该地区白垩纪—古近纪海相地层记录了东特提斯洋演化和一系列重大地质事件,具有重要的研究价值,但对其地层的研究仍相对薄弱,对重大地质事件的研究还不够深入。本文拟通过详细的岩石地层、生物地层和其他地层方法,完善地层划分与对比框架,并在此基础上讨论Cenomanian/ Turonian界线大洋缺氧事件(OAE2)、白垩纪/古近纪界线(K/Pg)、古新世—始新世极热事件(PETM)、特提斯海进与海退等一系列重大地质事件。塔里木盆地白垩纪—古近纪海相或海陆过渡相地层自下而上为克孜勒苏群、库克拜组、乌依塔克组、依格孜牙组、吐依洛克组、阿尔塔什组、齐姆根组、盖吉塔格组、卡拉塔尔组、乌拉根组和巴什布拉克组,上述地层中含有丰富的有孔虫、介形虫、钙质超微、沟鞭藻、孢粉、双壳类、腹足类等化石,以及少量菊石、腕足类、海胆和鲨鱼牙齿等化石。综合的生物地层和年代地层研究表明,克孜勒苏群的时代为早白垩世Barremian-Albian期,库克拜组—依格孜牙组的时代为晚白垩世Cenomanian-Maastrichtian期(Cenomanian/Turonian界线可能位于库克拜组三段),吐依洛克组的时代为白垩纪—古近纪过渡期;阿尔塔什组的时代为古新世早中期,齐姆根组为古新世晚期—始新世最早期,盖吉塔格组—乌拉根组的时代为中始新世中晚期,巴什布拉克组的时代为晚始新世,但不排除最上部进入渐新世早期。塔里木盆地的海侵开始于克孜勒苏群中上部沉积期(Albian晚期—Aptian早期),但规模很有限,大规模的海侵始于晚白垩世Cenomanian早期;从晚白垩世—古新世,共经历了5次大规模的海侵—海退事件;大约41 Ma前后,海水退出盆地南部的昆仑山山前,34 Ma前后,海水退出盆地北部的天山山前。上述海侵—海退事件可能受构造和全球海平面变化的双重影响,但构造事件对海侵的启动和结束可能更具决定性的影响。阐述了塔里木盆地西部白垩纪—古近纪海相地层所记录的OAE2、K/Pg界线、PETM和特提斯海侵—海退等事件,其中笔者及团队第一次在塔里木盆地西部齐姆根组中所发现和报道的PETM事件,将有助于揭示全球近岸地区PETM的特征和生物-环境响应。在未来的研究中,需要进一步厘清塔里木盆地西部地层序列,建立更加精细的生物地层和年代地层框架,加强对PETM和特提斯海侵—海退等重大地质事件的研究。