Single-Link Cluster Method to Identify Foreshocks and Aftershocks

Based on Single-Link Cluster (SLC) analysis,a new method to identify the foreshocks andaftershocks of a strong shock from the earthquake catalogue and then to form a sequencecatalogue has been proposed in this paper.In the SLC frame,there are many chains formedby links with lengths shorter than or equal to the characteristic length Lc.It is defined thatwhen some of these chains connect with a strong shock,the seismic events on such chainsfirm a sequence with the strong shock.In this sequence,the strong shock is the main shock;the events preceding the main shock are foreshocks and those following the main shock areaftershocks.By using this method,the foreshocks and aftershocks associated with the M_s7.4Haicheng earthquake and with the strong shocks of M_s≥6.0 in the top area of Kunlun-AltunArc were identified and sequence catalogues for these strong shocks were set up.     

锡矿山超大型锑矿床流体成矿作用及矿床成因

本文对锡矿山流体包裹体,稳定同位素,活动性微量元素,硅化作用及元素存在相态和淋滤率进行了详细研究。揭示了其成矿流体来源于深循环大气降水,是一种中低温,低盐度的弱碱性流体,成矿物质来自于前泥盆系地层,主要是震旦,寒武系地层,区域地层可能经受过大规模的流体运移作用。得出了锡矿山锑矿是由深循环大气降水林滤基底地层的成矿物质后形成含矿流体沿主断裂向上运移至浅部,由于物理化学条件的改变导致锑沉淀成矿的结论。     

边界层风廓线雷达资料在北京夏季强降水天气分析中的应用

利用北京城区及周围3个站的Airda 3000边界层风廓线雷达提供的风廓线资料,详细分析了北京2005年8月3日的一次强降水天气过程.分析表明,降水前十几小时出现双层低空急流,急流层内结构复杂,呈现多中心结构.风廓线观测揭示,南高空槽和弱冷空气共同诱发产生的切变线低涡是产生此次暴雨天气的主要中尺度系统,暴雨系统有很复杂的垂直结构.强降水开始前数小时(夜间)城区地面风场辐合,在临近降水和降水开始时辐合(或切变)层向上发展,这一过程有利于降水的发展.     

我国城市考古中翼手目遗骸的首次发现及其生态、资源域分析

翼手目是哺乳动物纲中唯一真正会飞翔的动物。中国旧石器时代遗址中已发现较多,新石器时代遗址中鲜有发现,城市遗址考古中重庆南宋府衙遗址为首次发现。2012年重庆南宋府衙遗址H43考古发掘中,通过使用水洗法获得2件小褐菊头蝠（Rhinolophus stheno）下颌骨标本。下颌骨齿式为2·1·3·3,下齿列长度7.82~7.87mm。骨骼材料属于菊头蝠科（Rhinolophidae）小型类型。下颌骨的p3高度退化,生长位置完全退出于下齿列中轴线外侧;p2和p4齿冠直接接触。下臼齿m1~m3齿冠结构相似,齿冠底部前面-颊侧-后面,生长有明显的齿带（前高、后低）;下内尖比下次尖弱小;3枚下臼齿从前向后,呈现微弱的规律性变小现象（m3不呈现特别退化现象）。小褐菊头蝠现生区域,是从赤道一带沿马来半岛（马来西亚）、中南半岛（包括越南、老挝、泰国等）向北回归线附近分布,生存区域主要为热带雨林气候区和热带季风气候区。重庆南宋府衙遗址小褐菊头蝠的发现,证实宋代中国西南峡谷低海拔区域,存在有与热带季风气候区相近似的自然环境特征。该批标本发现于宋代重庆主城区,反映当时重庆主城区阔叶林竹林等原生植被繁茂,自然水域较多并很少受到人类干扰。城市居民生活资料并非是依靠对城内资源进行开发和索取,而主要依靠城市之外的社会供给渠道向城内提供。这一认识为历史时期都市资源域特点找到了例证,也为现代“森林城市”建设理念找到了历史模板。东南亚型翼手目小褐菊头蝠发现于重庆古遗址,还反映中国西南地区古动物群与东南亚古动物群之间,具有很大共同性和密切演化关系。

     

安徽宣城红土微生物GDGTs分布特征及其古环境意义

中国南方更新世红土是古气候环境变化研究非常重要的载体之一,红土微生物类脂分子是其古气候环境研究的有效指标,但其在红土中的古气候意义需要更进一步的挖掘和明确.选取处于气候变化敏感地带并且已有很好年代学基础的安徽宣城红土剖面进行详细的野外调查和系统的样品采集,利用改善后的碱式水解法提取红土微生物类脂分子,通过对比分析、比较印证等方法对其中的甘油二烷基链甘油四醚(glycerol dialkyl glycerol tetraethers,简称GDGTs)进行系统研究.宣城剖面GDGTs分布特征显示:剖面下部各指标呈旋回性变化、而上部相对稳定,表明形成初期环境比较动荡,而后期成土环境相对稳定;土壤pH为7.0~8.0,推测其物源主要来源于北方干旱区或长江中下游干涸河滩沉积;BIT指标反映宣城地区在130 ka BP左右气候极为干旱.结果表明,红土中微生物类脂物GDGTs能够定量、高分辨率地重建安徽宣城的古气候环境,具有重要的研究意义.      

Discovery of the early Jurassic Gajia mélange in the Bangong–Nujiang suture zone: Southward subduction of the Bangong–Nujiang Ocean?

International Journal of Earth Sciences - Mélange records a series of geological processes associated with oceanic subduction and continental collision. This paper reports for the first time...     

中国短期气候变化的一个重要原因——青藏高原地表反射率的变化

通过数值试验对高原地表反射率变化的气候效应进行了敏感性研究,同时对观测的近４０年中国区域气候变化趋势作了对比分析。结果表明,高原主体地表反射率增加是我国短期气候变化的重要控制因子之一,它能造成东亚夏季风和高原夏季风的显著减弱,使夏季我国东部季风区北方变暖,南方变冷,季风降水普遍减少。     

模糊优选神经网络模型在城市防洪规划方案优选中的应用

城市防洪规划方案的综合优选是一个涉及到政治、社会、经济、环境等多准则、多因素的复杂多目标决策问题.针对目前各种常用的综合优选模型应用中存在的指标权重选择及转换问题,利用模糊优选神经网络模型,构造了合理的网络拓扑结构并将模型应用于某城市的防洪规划方案综合优选中.实例结果表明,此模型不仅避免了对指标权重的处理问题,而且明显加快了BP网络的收敛速度.     

台风运动内在随机性的研究

本文用差分方法，对决定性的正压涡度方程实施了四组数值积分。根据模式输出量，求得了台风中心移速的一维序列和二维序列。计算了移速序列的关联维数和Ｋ熵。结果表明模式大气中台风中心的移动具有内在随机性。最后讨论了局域热源和基流对台风移动路径随机性和可预测性的影响。     

Status of Macrobenthic Community and Its Relationships to Trace Metals and Natural Sediment Characteristics

Laizhou Bay, located in the northwest of Shandong Peninsula, has complex transitional environments between terrestrial and marine ecosystems. In the present study, a total of 122, 131, and 139 species were collected in spring, summer, and autumn 2011, respectively. Species constitutions of macrobenthos were grouped into four phyla, of which annelida were the most abundant phylum, the average biomass proportion of echinodermata was the lowest, and the proportion of important species for mollusca was the highest. The structure of the macrobenthic community showed significant differences between sites, and greater divergence was observed between the third site (S03) and other stations. The ABC plots showed that the biomass curve lay below the abundance curve, and the W‐statistic value was negative. The result of the BOPA index showed that two stations had moderate ecological status in spring and that there were two heavily polluted sites and one moderately polluted site in summer. The BIO‐ENV analyses indicated that the grain‐size fractions together with trace metals (Hg, Pb, Zn, Cu, and Cr) could be considered as the major environmental variables influencing the macrobenthic patterns. The results together demonstrated that the macrobenthic communities in Laizhou Bay were negatively affected, perhaps by the tremendous impact of heavy metals in the sediments.