Spatial distribution and inducement of collapsed buildings in Yushu earthquake based on remote sensing analysis

At 7:49 a.m. on April 14th, 2010, an earthquake of 7.1 on the Richter scale occurred in Yushu County, Yushu Tibetan Autonomous Prefecture in Qinghai Province. There was great loss of property and life.     

Revision of thickness design of cylindrical frozen walls considering frost heave

This paper outlines development of the thickness design of cylindrical frozen walls in artificial ground freezing (AFG). A plain strain mechanical model coupled with infinite surrounding soil and rock ...     

阿尔金山北缘冰沟蛇绿混杂岩中辉长岩锆石SHRIMP U-Pb定年及其地质意义

冰沟蛇绿混杂岩是阿尔金山红柳沟蛇绿混杂岩带的东段部分,岩石组合包括蛇纹岩、方辉橄榄岩、辉石岩和辉长岩等。蛇纹岩具高Mg,Mg/Fe值大于9,低Al、Ca、Na、K为特征,从稀土元素和微量元素特征来看,基性辉长岩和洋壳以及洋中脊玄武岩极为相似,而超基性岩与原始地幔较为接近。辉长岩获得锆石SHRIMP年龄为449.5±10.9Ma。蛇绿混杂岩的围岩为一套巨厚的碎屑岩、火山碎屑岩、火山岩,以及部分碳酸盐岩构成,其中含有具有洋中脊特征的枕状构造玄武岩,以及放射虫硅质岩,放射虫时代为奥陶纪中晚期,与辉长岩的SHRIMP年龄一致。这些证据进一步证实了红柳沟一带存在早古生代洋盆的地质事实。     

Types and genetic mechanism of chrysoberyl depositsSCIEI北大核心CSCD

金绿宝石作为一种铍矿物,不仅能用于高新科技、军事、医疗等领域,也是一种珍贵的宝石。自十八世纪被发现以来,金绿宝石成因和矿床特征被广泛地关注与研究。本文梳理与归纳了金绿宝石矿物学特征、矿床类型与分布,并给出新的矿床划分方案;总结了金绿宝石矿床的形成机制和影响因素等方面研究进展及科学问题。金绿宝石矿床按照成因可分为四个大类,即熔体结晶类、变质成因类、交代成因类和风化成因类;而根据赋存岩石,可将金绿宝石矿床进一步划分为六种亚型,分别是花岗岩-伟晶岩型、变质伟晶岩型、蛇纹岩型、云母岩型、条纹岩型和砂矿型。金绿宝石可在高温的高分异花岗岩岩浆中直接结晶形成,主要与石英、长石、白云母、绿柱石等共生,也可见锌尖晶石、夕线石和红柱石;在高级变质条件下金绿宝石由绿柱石分解得到,在变质伟晶岩型中金绿宝石与长石和石英共生,而在蛇纹岩型中金绿宝石与硅铍石共生;由远端交代作用控制形成的条纹岩型金绿宝石常与萤石、硅铍石和塔菲石共生,而由近端交代作用控制形成的云母型金绿宝石则与金云母、绿柱石和硅铍石共生。金绿宝石矿床仍存在很多有待解决与深入探讨的科学问题：金绿宝石形成的温压范围比较大,可能存在不同晶体相;针对花岗岩-...     

The long-term trends (1982–2006) in vegetation greenness of the alpine ecosystem in the Qinghai-Tibetan Plateau

The increased rate of annual temperature in the Qinghai-Tibetan Plateau exceeded all other areas of the same latitude in recent decades. The influence of the warming climate on the alpine ecosystem of the plateau was distinct. An analysis of alpine vegetation under changes in climatic conditions was conducted in this study. This was done through an examination of vegetation greenness and its relationship with climate variability using the Advanced Very High Resolution Radiometer satellite imagery and climate datasets. Vegetation in the plateau experienced a positive trend in greenness, with 18.0 % of the vegetated areas exhibiting significantly positive trends, which were primarily located in the eastern and southwestern parts of the plateau. In grasslands, 25.8 % of meadows and 14.1 % of steppes exhibited significant upward trends. In contrast, the broadleaf forests experienced a trend of degradation. Temperature, particularly summer temperature, was the primary factor promoting the vegetation growth in the plateau. The wetter and warmer climate in the east contributed to the favorable conditions for vegetation. The alpine meadow was mostly sensitive to temperature, while the steppes were sensitive to both temperature and precipitation. Although a warming climate was expected to be beneficial to vegetation growth in the alpine region, the rising temperature coupled with reduced precipitation in the south did not favor vegetation growth due to low humidity and poor soil moisture conditions.     

新疆北山早二叠世岩浆型铜镍硫化物矿床 综合信息勘查模式

新疆北山发育有20～30个产于晚古生代北山裂谷带中的早二叠世超基性岩岩体。自2008年以来在坡北基性-超基性杂岩体中发现坡一大型镍矿床和坡十中型镍矿床。利用本项目资料结合前人研究成果,文章从构造、岩体基本特征、围岩条件、矿物学特征、化探异常特征、地球物理参数等多个方面总结了含矿岩体(相)与非含矿岩体(相)的区别。研究发现新疆北山铜镍矿矿床受深大断裂控制,多产于深大断裂一侧的次级断裂中。在预查阶段或预查以前,可以首先利用1∶20万和1∶5万勘查地球化学数据,对Cu、Ni、Co、Cr异常区进行调查研究,同时辅以ETM遥感线环解译、1∶5万航磁资料的化极和向上延拓图(关注高磁异常)和1∶5万重力资料的布格重力异常(关注△GB-142×10 g.u的区域)来圈定区域上的基性超基性岩体。地表的孔雀石蚀变、黄钾铁矾和镍华是寻找铜镍矿的重要线索。在普查阶段,若存在纯橄岩且岩相分异良好的杂岩体,则更有可能发现铜镍矿。同一地区,具有高Cr尖晶石且尖晶石Fe3+/∑Fe0.3的基性-超基性杂岩体,成铜镍矿的潜力更大;含最超基性或接近最超基性的岩相的岩体成铜镍矿的可能性更大;含有高Fo、高NiO、低FeO*、低CaO、低TiO2的橄榄石且低Fe、Ca含量辉石的岩相是铜镍矿勘查的优选岩相。围岩有硫化物、硫酸盐或石墨层的超基性岩体的成矿潜力要大于围岩为无硫化物方解石大理岩的超基性岩体的成矿潜力。在此基础上,瞬变电磁(TEM)方法获得的瞬变响应感应电动势的垂直分量DBz/Dt(1.2)数据和可控源声频大地电磁可以用来推断深部超基性岩体的分布,是深部验证的重要依据。三维磁化率反演可以为矿区的定位预测或确定超基性岩体的延伸情况提供一定的依据。井中磁测可以作为防止漏矿的一种补充方法。在详查阶段,通过精细钻孔编录和三维软件查明矿体的空间展布趋势规律可为定位预测提供依据。文章总结了针对新疆北山地区铜镍硫化物矿床的综合信息勘查模型和勘查策略,并对硫化物饱和机制进行了探讨。     

Quantitative estimation of the shrub canopy LAI from atmosphere-corrected HJ-1 CCD data in Mu Us Sandland

The leaf area index (LAI) is an important ecological parameter that characterizes the interface between vegetation canopy and the atmosphere. In addition, it is used by most process-oriented ecosystem models. This paper investigates the potential of HJ-1 CCD data combined with linear spectral unmixing and an inverted geometric-optical model for the retrieval of the shrub LAI in Wushen Banner of Inner Mongolia in the Mu Us Sandland. MODTRAN (Moderate Resolution Atmospheric Radiance and Transmittance Model) was used for atmospheric correction. Shrubland was extracted using the threshold of the normalized difference vegetation index, with which water bodies and farmland were separated, in combination with a vegetation map of the People’s Republic of China (1:1000000). Using the geometric-optical model, we derive the per-pixel reflectance as a simple linear combination of two components, namely sunlit background and other. The fraction of sunlit background is related to the shrub LAI. With the support of HJ-1 CCD data, we employ linear spectral unmixing to obtain the fraction of sunlit background in an atmospherically corrected HJ image. In addition, we use the measured shrub canopy structural parameters for shrub communities to invert the geometric-optical model and retrieve the pixel-based shrub LAI. In total, 18 sample plots collected in Wushen Banner of Inner Mongolia are used for validation. The results of the shrub LAI show good agreement with R ² of 0.817 and a root-mean-squared error of 0.173.     

三河—平谷地区地脉动H/V谱比法探测:场地响应、浅层沉积结构及其反映的断层活动

1679年三河—平谷8级地震,造成了包括北京在内的华北广大地区严重的人员和经济损失,但是该地区和地震灾害密切相关的沉积结构和地震场地响应特征研究,相对比较缺乏.本文利用1~4 km台间距的高密度单台地脉动观测、几个小孔径台阵观测和钻孔测井数据,研究了三河—平谷地区的浅层沉积的场地响应和沉积层三维起伏特征,以及构造运动对沉积厚度的影响.结果表明,研究区沉积层的场地共振频率和沉积厚度有明显的分区特征：东北部场地共振频率主要在1.0~7.0 Hz之间,具有相对较薄的沉积厚度,沉积界面起伏也相对平稳;西南部场地共振频率大部分区域小于1.0 Hz,可低至0.3 Hz,相应的沉积厚度起伏显著,其中在大厂凹陷厚度可达300~600 m.沉积起伏和隐伏断裂带的分布有较好的对应关系,反映了夏垫断裂、南苑—通县断裂第四纪以来较为活跃的正断活动.北东走向的夏垫等隐伏断裂在东北部山前的正断活动相对不发育,以及东北部和西南部沉积厚度的显著差异,都可能受到北西走向的二十里长山断裂带活动的影响.按照Vs30场地分类,研究区内沉积较厚的凹陷地区主要为E类软土,其他区域为D类中硬土.研究结果与区域地质调查、钻孔数据和浅层地震勘探剖面结果基本相符,说明地脉动探测方法能够高效、低成本的获取区域沉积厚度和场地作用,为地震小区划和抗震设防提供有意义的参考.     

Cratering process and morphological features of the Xiuyan impact crater in Northeast China

By using crater impact morphological theory and mathematics modeling,the paper studies the cratering process and morphological features of the Xiuyan Crater in Northeast China based on remote sensing imagery,digital elevation model(DEM)and drilling and measuring data.The results show that:1)Simulated calculation indicates the diameter of the transient crater was1406±12 m and the depth was 497±4 m.The diameter of the final crater was 1758±15 m and the depth was 374.5±3.5 m;the thickness of the breccia lens was 188.5±0.5 m.The data is basically the same as previous drilling data.2)Preliminary determination of the size of Xiuyan impactor:The diameter at about 55 m for an iron meteorite,and about 115 m for a stony meteorite.3)The depth-to-diameter ratio is 0.143,similar to the typical simple crater.The circularity index of the Xiuyan Crater is0.884,indicating erosion and degradation.4)The distribution pattern of radial fractures has priority in NW-SE and WNW-ESE and these fractures control the development and evolution of drainage inside the crater.     

Conceptual study of lunar-based SAR for global change monitoring

As an active microwave remote sensing imaging sensor, Synthetic Aperture Radar (SAR) plays an important role in earth observation. Here we establish a SAR system based on the platform of the moon. This will aid large-scale, constant, and long-term dynamic Earth observations to better meet the needs of global change research and to complement the space borne and airborne earth observations. Lunar-based SAR systems have the characteristics of high resolution and wide swath width. The swath width could be thousands of kilometers in the stripe mode and it could cover 40% of earth’s surface with 10 meters or even higher spatial resolution in the scanning mode. Using the simplified observation model, here we quantitatively analyze the spatial resolution and coverage area of lunar-based SAR and simulate the observation on the Qinghai-Tibet plateau and the Amazon plain. The results show that this system could provide near 100% daily coverage of the Qinghai-Tibet plateau, whereas 40% to 70% daily coverage of the Amazon plain. Lunar-based SAR could provide large-scale, long-term and stable time series data in order to support future research of global change.